BACKGROUND OF THE INVENTION

[0001] Organic solvent nanofiltration (OSN) is a promising technology that can efficiently separate molecules in a range of 10-2,000 g mol ^-1 using highly stable solvent- resistant membranes capable of operating under harsh conditions. Despite its potential, technological advances in OSN membrane fabrication have been slow due to the challenges of preparing polymers with the requisite thermal stability and intrinsic porosity that are also solution processable and stable (not soluble) in organic solvents.

[0002] Polyether ether ketone (PEEK) is stable in organic solvents and thus a strong candidate for OSN membranes. However, the solubility of PEEK is limited to two undesirable and industrially problematic solvents - namely, methanesulfonic acid and sulfuric acid. Methanesulfonic acid and sulfuric acid are highly toxic, strong acids that pose health risks and thus are subject to strict regulatory control. Moreover, dissolving PEEK in these acids leads to a detrimental change in the polymer structure, namely sulfonation. Sulfonation is unavoidable and the extent or degree of sulfonation is difficult to control. Accordingly, final membrane separation performance can be highly inconsistent across PEEK membranes. In addition, PEEK is a compacted polymer. It is considered a semi-crystalline material with low fractional free volume and porosity.

[0003] While there has been some academic and commercial interest in PEEK for OSN applications, such interest has been limited to process development as opposed to materials development. For example, commercial PEEK for OSN applications has been reported, but the OSN membrane is made from strong acids. PEEK polymers that are soluble in NMP:THF have also been reported for OSN applications, but said polymers do not exhibit microporosity. Another report describes a process of preparing non-sulfonated PEEK membranes in which a commercial PEEK polymer is converted to a soluble non-PEEK precursor and the resulting membrane is subsequently hydrolyzed to convert back to the PEEK polymer. However, the resulting PEEK polymers similarly do not exhibit microporosity.

[0004] Accordingly, it would be desirable to advance materials development of PEEK polymers to overcome the aforementioned challenges, among others. SUMMARY OF THE INVENTION

[0005] Hybrid polyether ether ketone (PEEK) polymers, methods of synthesizing hybrid PEEK polymers, membranes comprising hybrid PEEK polymers, applications involving hybrid PEEK polymers, and the like are provided herein.

[0006] In one aspect, the present invention provides a method of synthesizing hybrid

PEEK polymers, the method comprising: wherein n is from 1 to 100,000; and one of Z and Z’ is an optionally substituted bivalent contorted structural group and one of Z and Z’ is an optionally substituted bivalent aromatic group, or Z and Z’ are both optionally substituted bivalent contorted structural groups, which can be the same or different, wherein the bivalent contorted structural group has the structure of formula (1): or an analogue, enantiomer, or stereoisomer of said bivalent contorted structural groups, wherein: is a point of attachment;

R ^a and R ^b are independently nothing, hydrogen, halogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted aralkenyl group, nitro group, amino group, or cyano group; and

Q is a moiety having a structure selected from formulas (2A) to (21):

wherein: is a point of attachment or an optional bond; R ¹ and R ² are each independently nothing, hydrogen, double-bonded O atom, halogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted aralkenyl group, nitro group, amino group, or cyano group, or R ¹ and R ² form a 5-membered ring;

W, if present, is single bond, — CCCF3)2 , — C(CH ₃ )2— , — C(H)=C(H)— , —

C(aryl)=C(aryl) — , — C(=0)— , , or — phenyl — , which can be substituted or unsubstituted, or fused to one or more 6-membered rings;

X, if present, is a C atom, heteroatom, or substituted or unsubstituted alkyl group, wherein each X can be independently selected;

Y, if present, is a C atom, heteroatom, substituted or unsubstituted alkyl group, or substituted or unsubstituted alkylene group; and

Ar, if present, is substituted or unsubstituted aryl group or substituted or unsubstituted heteroaryl group. [0007] In another aspect, the present invention provides a composition comprising a hybrid polyether ether ketone (PEEK) polymer having the structure of formula (I): wherein n is from 1 to 100,000; and one of Z and Z’ is an optionally substituted bivalent contorted structural group and one of Z and Z’ is an optionally substituted bivalent aromatic group, or Z and Z’ are both optionally substituted bivalent contorted structural groups, which can be the same or different; wherein the bivalent contorted structural group has the structure of formula (1) (defined above).

[0008] In a further aspect, the present invention provides membranes comprising the hybrid PEEK polymers disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic diagram illustrating the preparation of an PIM-PEEK-SBI membrane using a phase inversion method, according to one or more embodiments of the invention. [0010] FIGS. 2A-2F are graphical views relating to the characterization of PIM-PEEK- SBI polymers with low and high molecular weights: a) ¹ H nuclear magnetic resonance ( ¹ H NMR); b) Fourier-transform infrared (FTIR) spectra; c) gel permeation chromatography (GPC) elution curves; d) thermogravimetric analysis (TGA) in a nitrogen atmosphere; e) thermal glass transition temperature obtained using differential scanning calorimetry (DSC); f) solubility tests in 40 different solvents for PIM-PEEK-SBI (green circles refer to green solvents; and a filled or empty circle refers respectively to the polymer’s solubility or insolubility in a given solvent, according to one or more embodiments of the invention.

[0011] FIGS. 3A-3P are presented to show the PIM-PEEK-SBI membrane surface morphology at (a-d) high and (e-h) low magnifications and (i-1) cross-sectional images, with the images in the insets showing water contact angles (WCAs) of the membrane surface; and surface roughness is documented through (m-p) atomic force microscope (AFM) images, according to one or more embodiments of the invention.

[0012] FIG. 4 is a Feret diameter distribution of the honeycomb pattern for each membrane, as obtained using ImageJ software from scanning electron microscope (SEM) surface images with 1200-μm ² area (Legend: Ml, M2, and M3: open, ajar, and tight membranes prepared using PIM-PEEK-SBI ^l , respectively), according to one or more embodiments of the invention.

[0013] FIGS. 5A-5G are graphical views illustrating a) molecular weight cutoff graphs of the four membranes (M0-M3); b) calculated pore diameter plot; c) rejection of dyes and APIs as functions of molecular weight (M _w ); d) flux versus pressure plot; e) solvent permeances (e) and swelling (f) of the membranes as functions of binding energies between the solvents and polymer chains obtained from MD simulations; g) nanofiltration performance of PIM- PEEK-SBI ^l relative to that of PIM-PEEK-SBI* and previously reported SPEEK membranes, according to one or more embodiments of the invention.

[0014] FIGS. 6A-6B are graphical views illustrating a) decrease in flux as functions of time for M0 and Ml membranes; and b) long-term stability during continuous operation of the Ml membrane for fresh and aged samples (Legend: M0: open membrane prepared using PIM- PEEK-SBI*; Ml: open membrane prepared using PIM-PEEK-SBI ^l , respectively), according to one or more embodiments of the invention.

[0015] FIGS. 7A-7B are SEM images of a PIM-PEEK-SBI (low molecular weight) membrane showing the surface morphology of said membrane, according to one or more embodiments of the invention. DETAILED DESCRIPTION

Definitions

[0016] The terms recited below have been defined as described below. All other terms and phrases in this disclosure shall be construed according to their ordinary meaning as understood by one of skill in the art.

[0017] denotes a point of attachment and/or an optional bond, with the proviso that double bonds are not contiguous.

[0018] When a bond is directed to the middle of a ring, this indicates that optionally 1 to 5 functional groups, R, are attached to the ring, with each R group being independently selected from among the recited options.

[0019] As used herein, the term “bivalent” refers to any group having at least two points of attachment; or that is capable of bonding to, or is bonded to, at least two other groups. The term includes groups having two or more points of attachment. For example, tervalent groups would be included within the meaning of the term “bivalent” because tervalent groups have three points of attachment which satisfies the requirement of having at least two points of attachment.

[0020] As used herein, the term “alkyl” refers to a straight or branched hydrocarbon chain radical comprising carbon and hydrogen atoms, containing no unsaturation, and having from one to ten carbon atoms (i.e., C1-C10 alkyl). Whenever it appears herein, a numerical range such as “1 to 10” refers to each integer in the given range; e.g., “1 to 10 carbon atoms” means that the alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 10 carbon atoms, although the present definition also covers the occurrence of the term “alkyl” where no numerical range is designated. In some embodiments, it is a C1-C4 alkyl group. Typical alkyl groups include, but are in no way limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, septyl, and the like. The alkyl is attached to the rest of the molecule by a single bond. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=0)0R ^k , — OC(=0)N(R ^k )2, — N(R ^k ) ₂ , — C(=0)R ^k , — C(=0)OR ^k , — C(=0)N(R ^k )2, — N(R ^k )C(=0)R ^k , — N(R ^k )C(=0)0R ^k , — N(R ^k X:(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl. [0021] As used herein, the term “aromatic” or “aryl” refers to an aromatic radical with six to ten ring atoms (i.e., C6-C10 aromatic or C6-C10 aryl) which has at least one ring having a conjugated pi electron system which is carbocyclic (e.g., phenyl, fluorenyl, and naphthyl). Whenever it appears herein, a numerical range such as “6 to 10” refers to each integer in the given range; e.g., “6 to 10 ring atoms” means that the aryl group may consist of 6 ring atoms, 7 ring atoms, etc., up to and including 10 ring atoms. The term includes monocyclic or fused- ring polycyclic (i.e., rings which share adjacent pairs of ring atoms) groups. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=0)0R ^k , — OC(=0)N(R ^k )2, — N(R ^k ) ₂ , — C(=0)R ^k , — C(=0)OR ^k , — C(=0)N(R ^k )2, — N(R ^k )C(=0)R ^k , — N(R ^k )C(=0)OR ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl. [0022] As used herein, the term “heteroaryl” refers to a 5- to 18-membered aromatic radical (i.e., C5-C18 heteroaryl) that includes one or more ring heteroatoms selected from nitrogen, oxygen and sulfur, and which may be a monocyclic or polycyclic ring system (e.g., bicyclic, tricyclic, tetracyclic ring systems, etc.). Whenever it appears herein, a numerical range such as “5 to 18” refers to each integer in the given range; e.g., “5 to 18 ring atoms” means that the heteroaryl group may consist of 5 ring atoms, 6 ring atoms, etc., up to and including 18 ring atoms. An N-containing “heteroaryl” moiety refers to an aromatic group in which at least one of the skeletal atoms of the ring is a nitrogen atom. The polycyclic heteroaryl group may be fused or non-fused. The heteroatom(s) in the heteroaryl radical, e.g., nitrogen or sulfur, is optionally oxidized. One or more nitrogen atoms, if present, are optionally quaternized. The heteroaryl is attached to the rest of the molecule through any atom of the ring(s). Examples of heteroaryls include, but are not limited to, azepinyl, acridinyl, benzimidazolyl, benzindolyl, 1,3-benzodioxolyl, benzooxazolyl, benzo[d]thiazolyl, benzothiadiazolyl, benzo[b][l,4]dioxepinyl, benzo[b][l,4]oxazinyl, 1,4-benzodioxanyl, benzonaphthofuranyl, benzoxazolyl, benzodioxolyl, benzodioxinyl, benzoxazolyl, benzopyranyl, benzopyranonyl, benzofuranyl, benzofuranonyl, benzofurazanyl, benzothiazolyl, benzothienyl, benzothieno[3,2-d]pyrimidinyl, benzotriazolyl, benzo[4,6]imidazo[l,2-a]pyridinyl, carbazolyl, cinnolinyl, cyclopenta[d]pyrimidinyl, 6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3- djpyrimidinyl, 5,6-dihydrobenzo[h]quinazolinyl, 5,6-dihydrobenzo[h]cinnolinyl, 6,7-dihydro- 5H-benzo [6,7]cyclohepta[ 1 ,2-c]pyridazinyl, dibenzofuranyl, dibenzothiophenyl, furanyl, furazanyl, furanonyl, furo[3,2-c]pyridinyl, 5 ,6,7 ,8 ,9, 10-hexahydracycloocta[d] pyrimidiny 1, 5,6,7,8,9,10-hexahydrocycloocta[d]pyridazinyl, 5,6,7,8,9,10-hexahydrocycloocta[d]pyridinyl, isothiazolyl, imidazolyl, indazolyl, indolyl, indazolyl, isoindolyl, indolinyl, isoindolinyl, isoquinolyl, indolizinyl, isoxazolyl, 5,8-methano-5,6,7,8-tetrahydroquinazolinyl, naphthyridinyl, 1,6-naphthyridinonyl, oxadiazolyl, 2-oxoazepinyl, oxazolyl, oxiranyl, 5,6,6a,7,8,9, 10, 10a-octahydrobenzo[h]quinazolinyl, 1 -phenyl- lH-pyrrolyl, phenazinyl, phenothiazinyl, phenoxazinyl, phthalazinyl, pteridinyl, purinyl, pyranyl, pyrrolyl, pyrazolyl, pyrazolo[3,4-d]pyrimidinyl, pyridinyl, pyrido[3,2-d]pyrimidinyl, pyrido[3,4-d]pyrimidinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrrolyl, quinazolinyl, quinoxalinyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl, 5,6,7,8-tetrahydroquinazolinyl, 5, 6,7,8- tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidinyl, 6,7,8,9-tetrahydro-5H- cyclohepta[4,5]thieno[2,3-d]pyrimidinyl, 5,6,7,8-tetrahydropyrido[4,5-c]pyridazinyl, thiazolyl, thiadiazolyl, thiapyranyl, triazolyl, tetrazolyl, triazinyl, thieno[2,3-d]pyrimidinyl, thieno[3,2-d]pyrimidinyl, thieno[2,3-c]pridinyl, and thiophenyl (i.e. thienyl). Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=0)0R ^k , — 0C(=0)N(R ^k )2, — N(R ^k ) ₂ , — C(=0)R ^k , — C(=0)0R ^k , — C(=0)N(R ^k )2, — N(R ^k )C(=0)R ^k , — N(R ^k )C(=0)0R ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl. Examples of monocyclic heteroaryls include, but are not limited to, imidazolyl, pyridinyl, pyrrolyl, pyrazinyl, pyrimidinyl, thiazolyl, furanyl and thienyl. [0023] As used herein, the term “halogen” or “halo” refers to fluoro, chloro, bromo and/or iodo. The terms “haloalkyl” refers to alkyl structures that are substituted with one or more halogen groups or combinations thereof.

[0024] As used herein, the term “cyano” refers to a — CN radical.

[0025] As used herein, the term “alkoxy” refers to an — O-alkyl radical, wherein alkyl is as described herein and contains 1 to 10 carbons (i.e., C1-C10 alkoxy). Whenever it appears herein, a numerical range such as “1 to 10” refers to each integer in the given range; e.g., “1 to 10 carbon atoms” means that the alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 10 carbon atoms. In some embodiments, it is a C1-C4 alkoxy group. Unless stated otherwise specifically in the specification, an alkoxy moiety may be substituted by one or more of the substituents described as suitable substituents for an alkyl radical.

[0026] As used herein, the term “cycloalkyl” refers to a monocyclic or polycyclic nonaromatic radical that contains carbon and hydrogen, and may be saturated, or partially unsaturated. Cycloalkyl groups include groups having from 3 to 10 ring atoms (i.e., C3-C10 cycloalkyl). Whenever it appears herein, a numerical range such as “3 to 10” refers to each integer in the given range; e.g., “3 to 10 carbon atoms” means that the cycloalkyl group may consist of 3 carbon ring atoms, 4 carbon ring atoms, 5 carbon ring atoms, etc., up to and including 10 carbon ring atoms. In some embodiments, it is a C3-C5 cycloalkyl radical. Illustrative examples of cycloalkyl groups include, but are not limited to the following moieties: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloseptyl, cyclooctyl, cyclononyl, cyclodecyl, and the like. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=O)0R ^k , — 0C(=O)N(R ^k ) ₂ , — N(R ^k )2, — C(=0)R ^k , — C(=0)OR ^k , — C(=0)N(R ^k ) ₂ , — N(R ^k )C(=0)R ^k , — N(R ^k )C(=0)OR ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl.

[0027] As used herein, the term “heterocycloalkyl” refers to a stable and not fully aromatic 3- to 18-membered ring (i.e., C3-C18 heterocycloalkyl) radical that comprises two to twelve ring carbon atoms and from one to six ring heteroatoms selected from nitrogen, oxygen and sulfur. Whenever it appears herein, a numerical range such as “3 to 18” refers to each integer in the given range; e.g., “3 to 18 ring atoms” means that the heterocycloalkyl group may consist of 3 ring atoms, 4 ring atoms, etc., up to and including 18 ring atoms. In some embodiments, it is a C5-C10 heterocycloalkyl. In some embodiments, it is a C4-C10 heterocycloalkyl. In some embodiments, it is a C3-C10 heterocycloalkyl. Unless stated otherwise specifically in the specification, the heterocycloalkyl radical may be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which may include fused or bridged ring systems. The heteroatoms in the heterocycloalkyl radical may be optionally oxidized. One or more nitrogen atoms, if present, may optionally be quatemized. The heterocycloalkyl radical may be partially or fully saturated. The heterocycloalkyl may be attached to the rest of the molecule through any atom of the ring(s). Examples of such heterocycloalkyl radicals include, but are not limited to, 6,7-dihydro-5H-cyclopenta[b]pyridine, dioxolanyl, thienyl[l,3]dithianyl, decahydroisoquinolyl, imidazolinyl, imidazolidinyl, isothiazolidinyl, isoxazolidinyl, morpholinyl, octahydroindolyl, octahydroisoindolyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2- oxopyrrolidinyl, oxazolidinyl, piperidinyl, piperazinyl, 4-piperidonyl, pyrrolidinyl, pyrazolidinyl, quinuclidinyl, thiazolidinyl, tetrahydrofuryl, trithianyl, tetrahydropyranyl, thiomorpholinyl, thiamorpholinyl, 1 -oxo-thiomorpholinyl, and 1 , 1 -dioxo-thiomorpholinyl. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=0)0R ^k , — 0C(=0)N(R ^k ) ₂ , — N(R ^k )2, — C(=0)R ^k , — C(=0)0R ^k , — C(=0)N(R ^k )2, — N(R ^k X:(=0)R ^k , — N(R ^k )C(=0)0R ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl.

[0028] As used herein, the terms “heteroalkyl”, “heteroalkenyl” and “heteroalkynyl” include optionally substituted alkyl, alkenyl and alkynyl radicals, which respectively have one or more skeletal chain atoms selected from an atom other than carbon, e.g., oxygen, nitrogen, sulfur, phosphorus or combinations thereof. A numerical range, which refers to the chain length in total, may be given. For example, C3-C4 heteroalkyl has a chain length of 3-4 atoms. For example, a — CH2OCH2CH3 radical is referred to as a “C4 heteroalkyl”, which includes the heteroatom in the atom chain length description. Connection to the rest of the molecule is through a carbon in the heteroalkyl chain. A heteroalkyl may be a substituted alkyl. The same definition applies to heteroalkenyl or heteroalkynyl. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=O)0R ^k , — 0C(=O)N(R ^k ) ₂ , — N(R ^k ) ₂ , — C(=0)R ^k , — C(=0)0R ^k , — C(=0)N(R ^k ) ₂ , — N(R ^k X:(=0)R ^k , — N(R ^k )C(=0)0R ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl.

[0029] As used herein, the term “carbocycle” and “carbocyclic” refers to alicyclic and aromatic cyclic structures, wherein the ring atoms consist of carbon atoms. For example, the term includes, but is not limited to, cycloalkyls, aryls, and the like.

[0030] As used herein, the term “heterocycle” and “heterocyclic” refers to alicyclic and aromatic cyclic structures, wherein the ring atoms include at least one heteroatom. For example, the term includes, but is not limited to, heteroaryls, heterocycloalkyls, and the like.

[0031] As used herein, the term “amino” or “amine” refers to a — N¾ radical group, [0032] As used herein, the term “alkenyl” refers to a straight or branched hydrocarbon chain radical group comprising carbon and hydrogen atoms, containing at least one double bond, and having from two to ten carbon atoms (i.e., C2-C10 alkenyl). Whenever it appears herein, a numerical range such as “2 to 10” refers to each integer in the given range; e.g., “2 to 10 carbon atoms” means that the alkenyl group may contain 2 carbon atoms, 3 carbon atoms, etc., up to and including 10 carbon atoms. In certain embodiments, an alkenyl comprises two to eight carbon atoms (i.e., C2-C8 alkenyl). In other embodiments, an alkenyl comprises two to five carbon atoms (i.e., C2-C5 alkenyl). The alkenyl is attached to the rest of the molecule by a single bond, for example, ethenyl (i.e., vinyl), prop-l-enyl, but-l-enyl, pent-l-enyl, penta- 1,4-dienyl, and the like. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=0)— R ^k , — 0C(=0)0R ^k , — 0C(=0)N(R ^k )2, — N(R ^k ) ₂ , — C(=0)R ^k , — C(=0)0R ^k , — C(=0)N(R ^k )2, — NO^C^)!^, — N(R ^k )C(=0)0R ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl.

[0033] As used herein, the term “aralkenyl” refers to an alkenyl as defined above that includes an aryl substituent.

[0034] As used herein, the term “alkynyl” refers to a straight or branched hydrocarbon chain radical group comprising carbon and hydrogen atoms, containing at least one triple bond, and having from two to ten carbon atoms (i.e., C2-C10 alkynyl). In some embodiments, an alkynyl group may contain one or more double bonds. Whenever it appears herein, a numerical range such as “2 to 10” refers to each integer in the given range; e.g., “2 to 10 carbon atoms” means that the alkynyl group may contain 2 carbon atoms, 3 carbon atoms, etc., up to and including 10 carbon atoms. In certain embodiments, an alkynyl comprises two to eight carbon atoms (i.e., C2-C8 alkynyl). In other embodiments, an alkynyl has two to five carbon atoms (i.e., C2-C5 alkynyl). The alkynyl is attached to the rest of the molecule by a single bond, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, and the like. Unless stated otherwise specifically in the specification, an alkenyl group is optionally substituted by one or more of the following substituents: alkyl, heteroalkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, halo, cyano, nitro, oxo, — OR ^k , — 0C(=O) — R ^k , — 0C(=O)0R ^k , — OC(=0)N(R ^k )2, — N(R ^k h, — C(=0)R ^k , — C(=0)OR ^k , — C(=0)N(R ^k ) ₂ , — N(R ^k )C(=0)R ^k , — N(R ^k )C(=O)0R ^k , — N(R ^k )C(=0)N(R ^k ) ₂ , wherein each of R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl. [0035] As used herein, the term “alkylamino” refers to a chemical moiety with formula

— N(R ^k )2, wherein each R ^k is independently hydrogen, alkyl, heteroalkyl, cycloalkyl, or heterocycloalkyl, and at least one R ^k is not hydrogen. Two R ^k s may optionally form a 3-8 membered ring.

[0036] “Moiety” refers to a specific segment or functional group of a molecule. Chemical moieties are often recognized chemical entities embedded in or appended to a molecule.

[0037] “Hydroxy” refers to a — OH radical.

[0038] “Oxo” refers to a =0 radical.

[0039] “Nitro” refers to a — NO2 radical.

[0040] “Substituted” means that the referenced group may be substituted with one or more additional group(s) individually and independently selected from acyl, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, hydroxy, alkoxy, mercapto, alkylthio, arylthio, cyano, halo, carbonyl, ester, thiocarbonyl, isocyanato, thiocyanato, isothiocyanato, nitro, perhaloalkyl, perfluoroalkyl, phosphate, alkylamino, and amino, and the protected derivatives thereof. The substituents themselves may be substituted, for example, a cycloalkyl substituent may have a halide substituted at one or more ring carbons, and the like. The protecting groups that may form the protective derivatives of the above substituents are known to those of skill in the art.

[0041] The term “optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and includes instances where the event or circumstance occurs and instances in which it does not. For example, “alkyl optionally substituted with” encompasses both “alkyl” and “alkyl” substituted with groups as defined herein. It will be understood by those skilled in the art, with respect to any group containing one or more substituents, that such groups are not intended to introduce any substitution or substitution patterns which would be deemed unacceptable by one of ordinary skill in the art.

Discussion

[0042] The present invention provides solution-processable hybrid polyether ether ketone (PEEK) polymers with high porosity. The hybrid PEEK polymers overcome the challenges of low porosity and limited solubility of conventional PEEK polymers by incorporated a contorted structural group into the backbone of a PEEK polymer (e.g., one or more phenyl rings of a conventional PEEK polymer can be replaced by a contorted structural group). The contorted structural group can have a kinked or contorted structure that limits the rotational freedom and conformational flexibility of the resulting hybrid PEEK polymer. Exemplary contorted structural groups will have highly rigid, kinked molecular structures and sterically hindered sites of contortion that restrict rotation of the hybrid PEEK polymer backbone and prevent efficient packing of polymer chains. The hybrid PEEK polymers can be easily synthesized by nucleophilic aromatic substitution reactions between a dihydroxyl monomer and difluoroketo monomer, provided that at least one of said monomers comprises a contorted structural group that is incorporated into the PEEK polymer backbone.

[0043] While the present disclosure provides a multitude of different hybrid PEEK polymers, one example of an exemplary hybrid PEEK polymer is one having a polymer of intrinsic microporosity (PIM) motif incorporated into the PEEK polymer backbone to yield hybrid PIM-PEEK polymers (Scheme 1 below):

Scheme 1 where R is a PIM motif, such as spirobisindane, Troger’s base, and triptycene. The PIM motifs have high rigidity that restricts rotation of the polymer backbone and sterically hindered contortion sites that prohibit efficient packing of polymer chains, thereby generating high fractional free volume. These hybrid PIM-PEEK polymers, and others, overcome the challenges associated with low porosity and difficult processability. [0044] The hybrid PEEK polymers disclosed herein have properties that are superior to conventional PEEK polymers. For example, the hybrid PEEK polymers can have intrinsic microporosity. In addition to possessing intrinsic microporosity, the hybrid PEEK polymers can be characterized by high fractional free volumes, high porosity, and high surface areas. Furthermore, the hybrid PEEK polymers can exhibit high stability (e.g., insoluble) in the presence of organic solvents, while also enjoying improved processability (e.g., solution processable). At least one advantage of the present invention is that the improved processability allows the hybrid PEEK polymers to be employed in the fabrication of membranes using solvents commonly used by the membrane manufacturing industry. For example, the hybrid polymers can exhibit good solubility in solvent falling into 15-25 Hildebrand Solubility Parameter (HSP) range. The hybrid PEEK polymers can also exhibit high thermal stability

(e.g., exceeding temperatures of 400 °C) and withstand harsh conditions.

[0045] In view of these features and others disclosed herein, the hybrid PEEK polymers can be utilized across numerous industries including without limitation the aerospace, pharmaceutical, industrial and specialty chemical, and electronic industries, among others. The hybrid PEEK polymers are particularly suited for organic solvent nanofiltrations. Additional applications in which the hybrid PEEK polymers be utilized include, but are not limited to, ultrafiltration applications, microfiltration applications, water and wastewater treatment applications, membrane-based gas separations (e.g., nitrogen enrichment via air separations; hydrogen recovery from nitrogen, methane, and/or carbon dioxide; acid gas removal in carbon dioxide/hydrogen sulfide liquid separations, gas storage applications, optoelectronic applications, 3D printing applications, sensing applications for trace substances, and the like. The hybrid polymers can also be utilized as high temperature adhesives and other composite materials.

Hybrid PEEK Polymers

[0046] Embodiments of the present invention include hybrid PEEK polymers having the structure of formula (I):

[0047] n is from 1 to 100,000, or 10,000; and [0048] Z and Z’ are independently a bivalent contorted structural group or bivalent aromatic group, each of which can be substituted or unsubstituted.

[0049] In some embodiments, at least one of Z and Z’ is a bivalent contorted structural group, which can be substituted or unsubstituted.

[0050] In some embodiments, one of Z and Z’ is a bivalent contorted structural group, which can be substituted or unsubstituted, and one of Z and Z’ is bivalent aromatic group, which can be substituted or unsubstituted. For example, in one embodiment, Z is a bivalent contorted structural group and Z’ is a bivalent aromatic group. In another embodiment, Z is a bivalent aromatic group and Z’ is a bivalent contorted structural group. In a further embodiment, Z and Z’ are bivalent contorted structural groups, which can be the same or different.

[0051] The bivalent aromatic group can be, or include, a bivalent organic moiety or a portion of a bivalent organic moiety having aromaticity but is not a contorted structural group. For example, in some embodiments, the bivalent aromatic group is, or includes, aryl groups and/or heteroaryl groups, each of which can be substituted or unsubstituted, and each having at least two points of attachment (e.g., such as arenediyls, heteroarenediyls, and the like). One example of an aromatic group is bivalent phenyl, or phenylene. In some embodiments, when Z’ is a bivalent aromatic group, said bivalent aromatic group having at least one point of attachment that is ortho or para to an electron withdrawing substituent (e.g., ketone group). [0052] In some embodiments, the bivalent aromatic group is, or includes, groups selected from phenyl, biphenyl, terphenyl, naphtyl, naphthalenyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, quinolinyl, isoquinolinyl, acridinyl, phenanthridinyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, pentalenyl, indenyl, naphthyl, azulenyl, heptalenyl, indacenyl, acenaphthyl, fluorenyl, spiro-bifluorenyl, benzofluorenyl, dibenzofluorenyl, phenalenyl, phenanthrenyl, anthracenyl, fluoranthenyl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl, picenyl, perylenyl, pentaphenyl, hexacenyl, pentacenyl, rubicenyl, coronenyl, ovalenyl, thiophenyl, furanyl, caibazolyl, indolyl, isoindolyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, benzocarbazolyl, dibenzocarbazolyl, dibenzosilolyl, and pyridinyl, each having at least two points of attachment or forming a portion of an organic moiety having at least two points of attachment.

[0053] In some embodiments, the bivalent aromatic group is selected from the following structures:

[0054] The bivalent contorted structural group can be, or include, a motif that enhances the porosity and/or fractional free volume of the hybrid PEEK polymer. For example, in some embodiments, the contorted structural groups can be or include motifs that restrict rotation of the polymer backbone and/or have sterically hindered sites of contortion that prohibit or prevent efficient packing of polymer chains.

[0055] In some embodiments, the bivalent contorted structural group is, or includes, a polymer of intrinsic microporosity (PIM), or a monomer thereof. Hybrid PEEK polymers comprising a PIM can be referred to herein as PIM-PEEK polymers. In some embodiments, the bivalent contorted structural group is selected from the group consisting of spirobisindane (SBI), Troger’s base (TB), and triptycene (TRIP), each of which can be substituted or unsubstituted. In some embodiments, the bivalent contorted structural group is selected from the group consisting of spirobisindane (SBI), Troger’s base (TB), triptycene (TRIP), spirobufluorene (SBF), ethanoanthracene (EA), binaphenyl (BIN), tetraphenylmethane (TPM), and tetraphenylethane (TPE), each of which can be substituted or unsubstituted. In some embodiments, the bivalent contorted structural group is selected from analogues, enantiomers, and/or stereoisomers of SBI, TB, TRIP, SBF, EA, BIN, TPM, and TPE. [0056] In some embodiments, bivalent contorted structural groups having the structure of formula (1) are provided:

[0057] or an analogue, enantiomer, or stereoisomer of said bivalent contorted structural groups, wherein:

[0058] is a point of attachment; [0059] R ^a and R ^b are independently nothing, hydrogen, halogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted aralkenyl group, nitro group, amino group, or cyano group; and [0060] Q is as defined below.

[0061] While the bivalent contorted structural group of formula (1) shows the points of attachment on different rings, the points of attachment can also be on the same ring. Representative examples of bivalent contorted structural groups having different configurations of the points of attachment include, without limitation, the following structures:

[0062] The groups R ^a and R ^b can be the same or different. Accordingly, in some embodiments, R ^a and R ^b are the same. In other embodiments, R ^a and R ^b are different.

[0063] In some embodiments, R ^a is nothing or hydrogen. In some embodiments, R ^a is a halogen selected from the group consisting of fluoro, chloro, bromo, and iodo. For example, in one embodiment, R ^a is fluoro. In another embodiment, R ^a is chloro. In a further embodiment, R ^a is bromo. In yet a further embodiment, R ^a is iodo. In some embodiments, R ^a is a haloalkyl group selected from the group consisting of trifluoromethyl, trichloromethyl, pentafluoroethyl, and pentachloroethyl. [0064] In some embodiments, R ^a is a linear or branched, substituted or unsubstituted alkyl group. In some embodiments, the linear or branched, substituted or unsubstituted alkyl group is a Ci-Cio alkyl, a C1-C6 alkyl, or a C ₁ -C ₄ alkyl. In some embodiments, R ^a is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec- pentyl, and the like. In one embodiment, R ^a is methyl. In another embodiment, R ^a is ethyl.

[0065] In some embodiments, R ^a is a substituted or unsubstituted alkoxy group. In some embodiments, the substituted or unsubstituted alkoxy group is a C ₁ -C ₁ 0 alkoxy, a C1-C6 alkoxy, or a C ₁ -C ₄ alkoxy. In some embodiments, R ^a is selected from — 0(CH ₃ ), — 0(CH ₂ CH ₃ ), —

0(CH ₂ ) ₂ CH3, — 0(CH ₂ ) ₃ CH ₃ , and the like.

[0066] In some embodiments, R ^a is a substituted or unsubstituted aryl group. In some embodiments, the substituted or unsubstituted aryl group is selected from phenyl, naphthyl, benzyl, and diphenylethane. In some embodiments, R ^a is a substituted or unsubstituted heteroaryl group comprising at least one of N heteroatom, S heteroarom, and O heteroatom. In some embodiments, the substituted or unsubstituted heteroaryl group is selected from furanyl, imidazyl, pyranyl, pyrrolyl, and pyridyl.

[0067] In some embodiments, R ^a is a substituted or unsubstituted aralkenyl group. In some embodiment, the substituted or unsubstituted aralkenyl group is a C ₂ -C ₆ alkenyl comprising a phenyl, naphtyl, or benzyl substituent. For example, in certain embodiments, R ^a is diphenylethenyl.

[0068] In some embodiments, R ^a is a double-bonded O atom. In some embodiments, R ^a is — NCh. In some embodiments, R ^a is — CN. In some embodiments, R ^a is — NH ₂ . In some embodiments, R ^a is — N(R ^C ) ₂ , wherein each R ^c is independendy an alkyl group, cycloalkyl group, heterocycloalkyl group, aryl group, or heteroaryl group, each of which can be substituted or unsubstituted. In some embodiments, each R ^c is phenyl. In some embodiments, each R ^c forms a 5-membered ring fused to two 6-membered carbocycles or heterocycles.

[0069] In some embodiments, R ^b is nothing or hydrogen. In some embodiments, R ^b is a halogen selected from the group consisting of fluoro, chloro, bromo, and iodo. For example, in one embodiment, R ^b is fluoro. In another embodiment, R ^b is chloro. In a further embodiment, R ^b is bromo. In yet a further embodiment, R ^b is iodo. In some embodiments, R ^b is a haloalkyl group selected from the group consisting of triluoromethyl, trichloromethyl, pentafluoroethyl, and pentachloroethyl.

[0070] In some embodiments, R ^b is a linear or branched, substituted or unsubstituted alkyl group. In some embodiments, the linear or branched, substituted or unsubstituted alkyl group is a C ₁ -C ₁ 0 alkyl, a C1-C6 alkyl, or a C ₁ -C ₄ alkyl. In some embodiments, R ^b is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec- pentyl, and the like. In one embodiment, R ^b is methyl. In another embodiment, R ^b is ethyl.

[0071] In some embodiments, R ^b is a substituted or unsubstituted alkoxy group. In some embodiments, the substituted or unsubstituted alkoxy group is a Ci-Cio alkoxy, a C1-C6 alkoxy, or a C1-C4 alkoxy. In some embodiments, R ^b is selected from — 0(CH ₃ ), — 0(CH ₂ CH ₃ ), —

0(CH ₂ ) ₂ CH3, — 0(CH ₂ ) ₃ CH ₃ , and the like.

[0072] In some embodiments, R ^b is a substituted or unsubstituted aryl group. In some embodiments, the substituted or unsubstituted aryl group is selected from phenyl, naphthyl, benzyl, and diphenylethane. In some embodiments, R ^b is a substituted or unsubstituted heteroaryl group comprising at least one of N heteroatom, S heteroarom, and O heteroatom. In some embodiments, the substituted or unsubstituted heteroaryl group is selected from furanyl, imidazyl, pyranyl, pyrrolyl, and pyridyl. [0073] In some embodiments, R ^b is a substituted or unsubstituted aralkenyl group. In some embodiment, the substituted or unsubstituted aralkenyl group is a C ₂ -C ₆ alkenyl comprising a phenyl, naphtyl, or benzyl substituent. For example, in certain embodiments, R ^b is diphenylethenyl.

[0074] In some embodiments, R ^b is a double-bonded O atom. In some embodiments, R ^b is — NO2. In some embodiments, R ^b is — CN. In some embodiments, R ^b is — NH ₂ . In some embodiments, R ^b is — N(R ^c )2, wherein each R ^c is independently alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, each of which can be substituted or unsubstituted. In some embodiments, each R ^c is phenyl. In some embodiments, each R ^c forms a 5-membered ring fused to two 6-membered carbocycles or heterocycles.

[0075] In some embodiments, the bivalent contorted structural unit includes a Q group having the structure of formulas (2A) to (21):

[0076] wherein:

[0077] is a point of attachment or an optional bond;

[0078] R ¹ and R ² are each independently nothing, hydrogen, double-bonded O atom, halogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, substituted or unsubstituted aralkenyl group, nitro group, amino group, or cyano group, or R ¹ and R ² form a 5-membered ring; [0079] W, if present, is single bond, — C(CF3) ₂ — , — C(CH3)2—: , — C(H)=C(H)— , —

C(aryl)=C(aryl) — , — C(=0)— , , or — phenyl — , which can be substituted or unsubstituted, or fused to one or more 6-membered rings;

[0080] X, if present, is a C atom, heteroatom, or substituted or unsubstituted alkyl group, wherein each X can be independently selected;

[0081] Y, if present, is a C atom, heteroatom, substituted or unsubstituted alkyl group, or substituted or unsubstituted alkylene group; and

[0082] Ar, if present, is substituted or unsubstituted aryl group or substituted or unsubstituted heteroaryl group. [0083] The groups R ¹ and R ² can be the same or different. In some embodiments, R ¹ and R ² are the same. In other embodiments, R ¹ and R ² are different.

[0084] In some embodiments, R ¹ is nothing or hydrogen. In some embodiments, R ¹ is a halogen selected from the group consisting of fluoro, chloro, bromo, and iodo. For example, in one embodiment, R ¹ is fluoro. In another embodiment, R ¹ is chloro. In a further embodiment, R ¹ is bromo. In yet a further embodiment, R ¹ is iodo. In some embodiments, R ¹ is a haloalkyl group selected from the group consisting of triluoromethyl, trichloromethyl, pentafluoroethyl, and pentachloroethyl.

[0085] In some embodiments, R ¹ is a linear or branched, substituted or unsubstituted alkyl group. In some embodiments, the linear or branched, substituted or unsubstituted alkyl group is a Ci-Cio alkyl, a C1-C6 alkyl, or a C ₁ -C ₄ alkyl. In some embodiments, R ¹ is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec- pentyl, and the like. In one embodiment, R ¹ is methyl. In another embodiment, R ¹ is ethyl.

[0086] In some embodiments, R ¹ is a substituted or unsubstituted alkoxy group. In some embodiments, the substituted or unsubstituted alkoxy group is a C ₁ -C ₁ 0 alkoxy, a C1-C6 alkoxy, or a C ₁ -C ₄ alkoxy. In some embodiments, R ¹ is selected from — 0(CH3), — 0(CH ₂ CH3), —

0(CH ₂ )2CH3, — 0(CH ₂ ) ₃ CH ₃ , and the like.

[0087] In some embodiments, R ¹ is a substituted or unsubstituted aryl group. In some embodiments, the substituted or unsubstituted aryl group is selected from phenyl, naphthyl, benzyl, and diphenylethane. In some embodiments, R ¹ is a substituted or unsubstituted heteroaryl group comprising at least one of a N heteroatom, S heteroarom, and O heteroatom. In some embodiments, the substituted or unsubstituted heteroaryl group is selected from furanyl, imidazyl, pyranyl, pyrrolyl, and pyridyl.

[0088] In some embodiments, R ¹ is a substituted or unsubstituted aralkenyl group. In some embodiment, the substituted or unsubstituted aralkenyl group is a C ₂ -C ₆ alkenyl comprising a phenyl, naphtyl, or benzyl substituent. For example, in certain embodiments, R ¹ is diphenylethenyl.

[0089] In some embodiments, R ¹ is a double-bonded O atom. In some embodiments, R ¹ is — NO2. In some embodiments, R ¹ is — CN. In some embodiments, R ¹ is — NH2. In some embodiments, R ¹ is — N(R ^C )2, wherein each R ^c is independendy alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, each of which can be substituted or unsubstituted. In some embodiments, each R ^c is phenyl. In some embodiments, each R ^c forms a 5-membered ring fused to two 6-membered carbocycles or heterocycles.

[0090] In some embodiments, R ² is nothing or hydrogen. In some embodiments, R ² is a halogen selected from the group consisting of fluoro, chloro, bromo, and iodo. For example, in one embodiment, R ² is fluoro. In another embodiment, R ² is chloro. In a further embodiment, R ² is bromo. In yet a further embodiment, R ² is iodo. In some embodiments, R ² is a haloalkyl group selected from the group consisting of triluoromethyl, trichloromethyl, pentafluoroethyl, and pentachloroethyl.

[0091] In some embodiments, R ² is a linear or branched, substituted or unsubstituted alkyl group. In some embodiments, the linear or branched, substituted or unsubstituted alkyl group is a C ₁ -C ₁ 0 alkyl, a C1-C6 alkyl, or a C ₁ -C ₄ alkyl. In some embodiments, R ² is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec- pentyl, and the like. In one embodiment, R ² is methyl. In another embodiment, R ² is ethyl. [0092] In some embodiments, R ² is a substituted or unsubstituted alkoxy group. In some embodiments, the substituted or unsubstituted alkoxy group is a C1-C10 alkoxy, a C1-C6 alkoxy, or a C1-C4 alkoxy. In some embodiments, R ² is selected from — 0(CH ₃ ), — 0(CH ₂ CH ₃ ), —

0(CH ₂ ) ₂ CH3, — 0(CH ₂ ) ₃ CH ₃ , and the like.

[0093] In some embodiments, R ² is a substituted or unsubstituted aryl group. In some embodiments, the substituted or unsubstituted aryl group is selected from phenyl, naphthyl, benzyl, and diphenylethane. In some embodiments, R ² is a substituted or unsubstituted heteroaryl group comprising at least one of N heteroatom, S heteroarom, and O heteroatom. In some embodiments, the substituted or unsubstituted heteroaryl group is selected from furanyl, imidazyl, pyranyl, pyrrolyl, and pyridyl.

[0094] In some embodiments, R ² is a substituted or unsubstituted aralkenyl group. In some embodiment, the substituted or unsubstituted aralkenyl group is a C1-C6 alkenyl comprising a phenyl, naphtyl, or benzyl substituent. For example, in certain embodiments, R ² is diphenylethenyl. [0095] In some embodiments, R ² is a double-bonded O atom. In some embodiments, R ² is — NO2. In some embodiments, R ² is — CN. In some embodiments, R ² is — NH2. In some embodiments, R ² is — N(R ^C )2, wherein each R ^c is independently alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, each of which can be substituted or unsubstituted. In some embodiments, each R ^c is phenyl. In some embodiments, each R ^c forms a 5-membered ring fused to two 6-membered carbocycles or heterocycles.

[0096] In some embodiments of the contorted structural groups of formulas (2A) and (2C), R ¹ and R ² and the atoms they attach to can form a 5-membered ring. In some embodiments, one pair of R1/R2 groups forms a 5-membered ring (e.g., the R1/R2 groups at either the top or bottom of the structure of formulas (2 A) and (2C)). In some embodiments, both of the R ^J /R ² groups form a 5-membered ring. The 5-membered ring formed from R ¹ and R ² can be substituted or unsubstituted. The 5-membered ring can be alicyclic or aromatic. The 5-membered ring can be heterocyclic or carbocyclic. In some embodiments, the 5-membered ring formed from R ¹ and R ² is fused to one or two 6-membered alicyclic or aromatic, substituted or unsubstituted, carbocycles or heterocycles. For example, in some embodiments, R ¹ and R ² form one of the following structures: where * is the spirocenter formed once R ¹ and R ² form a 5-membered ring.

[0097] In some embodiments, X is a C atom. In some embodiments, at least one X is a heteroatom selected from N heteroatom, S heteroatom, and O heteroatom. In some embodiments, each X is independently a C atom, N heteroatom, S heteroatom, or O heteroatom. In one embodiment, X is a nitrogen heteroatom. In some embodiments, at least one X is a C ₂ - C ₄ alkyl. In some embodiments, at least one X is selected from — CH — , — CHz — , — CH ₂ CH ₂ — , — CHCH2 — , or — CCH2 — , wherein at least one of the C atoms is bonded to R ¹ and/or R ² .

[0098] In some embodiments, Y is nothing. In some embodiments, Y is a C atom. In some embodiments, Y is a heteroatom selected from N heteroatom, S heteroatom, and O heteroatom. In some embodiments, Y is selected from the following structures: — CH2 — , — CH ₂ CH: , — CH=CH— ,

[0099] In some embodiments, Ar is substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl. In some embodiments, the substituted or unsubstituted aryl group is selected from phenyl, naphthyl, benzyl, and diphenylethane. In some embodiments, Ar is a substituted or unsubstituted heteroaryl group comprising at least one of a N heteroatom, S heteroarom, and O heteroatom. In some embodiments, the substituted or unsubstituted heteroaryl group is selected from furanyl, imidazyl, pyranyl, pyrrolyl, and pyridyl. In some embodiments, Ar is selected from the following structures:

[00100] Representative bivalent contorted structure groups include, without limitation, the following structures, including analogues, enantiomers, and/or stereoisomers thereof:

[00101] wherein:

[00102] is a point of attachment;

[00103] R ^a , R ^b , R ¹ , and R ² are as defined above.

[00104] Z and Z’ can independently include any of the bivalent contorted structural groups and optionally the bivalent aromatic groups disclosed herein to form a multitude of hybrid PEEK polymers. A person skilled in the art will readily appreciate the multitude of hybrid PEEK polymers included within the scope of the present disclosure. While the three embodiments discussed below are specific, said embodiments shall not be limiting for at least the foregoing reasons.

[00105] In one embodiment, the hybrid PEEK polymer has the following structure:

[00106] In another embodiment, the hybrid PEEK polymer has the following structure:

[00107] In a further embodiment, the hybrid PEEK polymer has the following structure:

[00108] In some embodiments, the hybrid PEEK polymers having the structure of formula (I) are soluble in solvents other than methanesulfonic acid, sulfuric acid, or both methanesulfonic acid and sulfuric acid. In some embodiments, the hybrid PEEK polymers having the structure of formula (I) are soluble in organic solvents. In some embodiments, the hybrid PEEK polymers having the structure of formula (I) are soluble in organic solvents selected from NMP, DMAc, cyrene, THE, dioxane, halogenated solvents such as DCM, chloroform, dichlorobenzene, and trichlorobenzene, and combinations thereof. In some embodiments, the hybrid PEEK polymers are soluble in said organic solvents and harsh acids like methanesulfonic acid and sulfuric acid, among others.

[00109] In some embodiments, the hybrid PEEK polymers having the structure of formula

(I) are characterized by BET surface areas in the range of about 0.2 m ² g ^'1 to about 1000 m ² g ^"

1 , or any incremental value or subrange between that range, inclusive. In one embodiment, the BET surface area is in the range of about 200 m ² g ^-1 to about 250 m ² g ^-1 .

[00110] In some embodiments, the hybrid PEEK polymers having the structure of formula (I) are characterized by a fractional free volume ranging from about 0.05 to about 0.45, including any incremental value or subrange between that range, inclusive. In one embodiment, the fraction free volume is in the range of about 0.200 to about 0.275. In another embodiment, the fraction free volume is in the range of about 0.203 to about 0.256.

[00111] Thermal stability is measured by evaluating the thermal decomposition temperature and particularly the 5% thermal decomposition temperature. In some embodiments, the hybrid PEEK polymers having the structure of formula (I) exhibits thermal stability at temperatures of about 600 °C or less, or any incremental value or subrange between that range, inclusive. In one embodiment, thermal stability is observed at temperatures exceeding 500 °C. In another embodiment, thermal stability is observed at temperatures exceeding 400 °C.

[00112] In some embodiments, the hybrid PEEK polymers having the structure of formula (I) are not semi-crystalline. In some embodiments, the hybrid PEEK polymers having the structure of formula (I) are amorphous.

[00113] In some embodiments, the hybrid PEEK polymers having the structure of formula (I) form non-sulfonated membranes, such as non-sulfonated PEEK membranes.

[00114] In some embodiments, the hybrid PEEK polymers have intrinsic porosity or intrinsic microporosity. In some embodiments, the hybrid PEEK polymer comprises a polymer of intrinsic microporosity (PIM) or a PIM motif. For example, in some embodiments, the hybrid PEEK polymer is a hybrid PIM-PEEK polymer.

Methods of Synthesizing Hybrid PEEK Polymers

[00115] Embodiments of the present invention further include methods of synthesizing hybrid PEEK polymers. The hybrid PEEK polymers can be synthesized by a nucleophilic aromatic substitution reaction between a dihydroxyl monomer and a difluoroketo monomer. For example, in some embodiments, the method of synthesizing hybrid PEEK polymers comprises:

[00116] wherein Z, Z’, and n are as defined above.

[00117] The reaction can proceed at any suitable temperature and thus is not particularly limited. The reaction will typically proceed at temperatures in the range of about 0 °C to about 200 °C, but temperatures outside of said range are permitted (e.g., temperatures ranging from -100 °C to about 300 °C). [00118] The solvent can influence reaction rate and selectivity, among other aspects of the invention. Examples of suitable solvents include, without limitation, dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), dimethylformamide, 1,4-dioxane, trimethylamine, chloroform, chlorobenzene, 1 -butanol, acetonitrile, and the like.

[00119] The molar ratio of dihydroxyl monomer to difluoroketo monomer can range from about 0.01:10 to 10:0.01. In some embodiments, an equimolar amount of the dihydroxyl monomer and difluoroketo monomer is used.

Hybrid PEEK Polymeric Membranes

[00120] Embodiments of the present invention further include membranes comprising any of the hybrid PEEK polymers disclosed herein. In some embodiments, the hybrid PEEK polymer membrane is a separation membrane. In some embodiments, the hybrid PEEK polymer membrane is a nanofiltration membrane. In some embodiments, the hybrid PEEK polymer membrane is an organic solvent nanofiltration membrane.

[00121] In some embodiments, the hybrid PEEK polymer membranes can be fabricated as integrally skinned asymmetric (ISA) membranes. For example, the hybrid PEEK polymer membranes can be fabricated by a phase inversion method involving (a) preparing a dope solution comprising a solubilized hybrid PEEK polymer, (b) casting the dope solution onto a support; (c) performing phase inversion of the cast dope solution (e.g., immersing in a nonsolvent bath); and (d) optionally exposing the resulting membrane to a temperature of about 20 °C or higher. The dope solution can be prepared with 50 wt.% or less of hybrid PEEK polymer, preferably between about 15 wt.% to about 35 wt.%. The hybrid PEEK polymer can be dissolved or solubilized in any suitable solvent (e.g., in step (a)), including without limitation NMP, DMAc, cyrene, polarclean, THF, dioxane, halogenated solvents such as DCM, chloroform, dichlorobenzene, and trichlorobenzene, combinations thereof, and the like. The non-solvent bath or coagulation bath used to perform phase inversion in step (c) can include water, among others.

[00122] The hybrid PEEK polymer molecular weight can be varied to fine-tune the membrane surface and/or enhance its separation performance. In some embodiments, the preparation of hybrid PEEK polymer membranes having a honeycomb surface and/or a flat surface may be achieved by varying the molecular weight of the hybrid PEEK polymers. For example, in some embodiments, the hybrid PEEK polymer membranes have a flat surface (e.g., when prepared from high molecular weight hybrid PEEK polymers). In some embodiments, the hybrid PEEK polymer membranes have a honeycomb surface (e.g., when prepared from low molecular weight hybrid PEEK polymers). In some embodiments, the pore size of the honeycomb surface can be controlled by varying the dope solution concentration. Molecular weight can vary from 1 kg mol ^-1 to 1000 kg mol ^-1 and the polymer dope solution concentration can be varied from 1% to 99%.

[00123] In some embodiments, the hybrid PEEK polymer membranes are non-sulfonated membranes. For example, the hybrid PEEK polymers can be dissolved or solubilized in non- sulfur-containing solvents, such as solvents other than methanesulfonic acid, sulfuric acid, and the like. Accordingly, the degree of sulfonation can be 0%.

[00124] The hybrid PEEK polymer membranes disclosed herein can be used as organic solvent nanofiltration membranes. For example, the hybrid PEEK polymer membranes can be used for performing nanofiltration in an organic solvent at temperatures in the range of 20 °C to about 400 °C. The hybrid PEEK polymer membranes are advantageously insoluble in a number of organic solvents, including, for example, polar aprotic organic solvents. In some embodiments, the hybrid PEEK polymer membranes are insoluble in acetonitrile, hexane, DMF, THF, and the like. Accordingly, a wide array of organic feed streams and operational temperatures can be used in nanofiltrations utilizing the hybrid PEEK polymer membranes of the present invention.

[00125] The following Examples are intended to illustrate the above invention and should not be construed as to narrow its scope. One skilled in the art will readily recognize that the Examiners suggest many other ways in which the invention could be practiced. It should be understood that numerous variations and modifications may be made while remaining within the scope of the invention.

Example 1 PIM-PEEK-SBI

[00126] Polyether ether ketones with polymer backbones into which polymers of intrinsic microporosity have been incorporated are referred to herein as PIM-PEEK or PIM-PEEK polymers.

[00127] PIM-PEEK-SBI polymers were prepared by nucleophilic aromatic substitution reaction (SNA _T ) by reacting a dihydroxyl spirobisindane with a 4,4’-difluorobenzophenone in an equimolar amount in DMAc at 165 °C for 20 hours. The obtained polymer fibers were treated and washed with hot water and methanol for few time and dried at 180 °C in the vacuum oven for 24 hours. The resulting PIM-PEEK-SBI had a BET surface area of 205 m ² g ^'1 and a 5% decomposition temperature of 495 °C. PIM-PEEK-SBI was found to be soluble in NMP, DMAc, cyrene and THE.

[00128] Having replaced the phenyl ring in a commercial PEEK polymer by contorted molecular structures, here spirobisindane, the physical properties of the PEEK polymer were modified. The commercial PEEK was a semi-crystalline material shown by XRD, whereas the PIM-PEEK-SBI polymer exhibited amorphous morphology also shown by XRD. The glass transition temperature of the PIM-PEEK polymers obtained by DSC were significantly higher than the conventional PEEK (T _g = 143 °C). For instance, T _g for PIM-PEEK-SBI = 243 °C.

Example 2 PIM-PEEK-TB

[00129] PIM-PEEK-TB polymers were prepared by nucleophilic aromatic substitution reaction (SNA _T ) by reacting a dihydroxyl Troger’s base with a 4,4’-difluorobenzophenone in an equimolar amount in DMAc at 165 °C for 20 hours. The obtained polymer fibers were treated and washed with hot water and methanol for few time and dried at 180 °C in the vacuum oven for 24 hours. The resulting PIM-PEEK-TB had a BET surface area of 220 m ² g ^-1 and a 5% decomposition temperature of 405 °C. PIM-PEEK-TB polymer was soluble in NMP, dioxane, and halogenated solvents such as DCM, chloroform, dichlorobenzene and trichlorobenzene. [00130] Having replaced the phenyl ring in a commercial PEEK polymer by contorted molecular structures, here Troger’s base, the physical properties of the PEEK polymer were modified. The commercial PEEK was a semi-crystalline material shown by XRD, whereas the PIM-PEEK-TB polymer exhibited amorphous morphology also shown by XRD. The glass transition temperature of the PIM-PEEK polymers obtained by DSC were significantly higher than the conventional PEEK (T _g = 143 °C). For instance, T _g for PIM-PEEK-TB = 197 °C.

Example 3 PIM-PEEK-Trip

[00131] PIM-PEEK-Trip polymers were prepared by nucleophilic aromatic substitution reaction (SNA _T ) by reacting a dihydroxyl triptycene with a 4,4’-difluorobenzophenone in an equimolar amount in DMAc at 165 °C for 20 hours. The obtained polymer fibers were treated and washed with hot water and methanol for few time and dried at 180 °C in the vacuum oven for 24 hours. The resulting PIM-PEEK-Trip had a BET surface area of 250 m ² g ^'1 and a 5% decomposition temperature of 526 °C. PIM-PEEK-Trip polymer was soluble in polarclean, NMP, DMAc, dioxane, and halogenated solvents such as DCM, chloroform, dichlorobenzene and trichlorobenzene.

[00132] Having replaced the phenyl ring in a commercial PEEK polymer by contorted molecular structures, here triptycene, the physical properties of the PEEK polymer were modified. The commercial PEEK was a semi-crystalline material shown by XRD, whereas the PIM-PEEK-Trip polymer exhibited amorphous morphology also shown by XRD. The glass transition temperature of the PIM-PEEK polymers obtained by DSC were significantly higher than the conventional PEEK (T _g = 143 °C). For instance, T _g for PIM-PEEK-Trip = 256 °C.

Example 4

PIM-PEEK Membranes

[00133] Dope solutions with different concentrations were prepared from the PIM-PEEK polymers of Examples 2 to 3 and used to prepare integrally skinned asymmetric (ISA) membranes by phase inversion method. NMP was used as the solvent to prepare a dope solution from the PIM-PEEK polymers, and water as a non-solvent for the coagulation bath. The obtained membranes demonstrated good flexibility and mechanical stability, which allowed their scale-up and the rolling of the flat sheet membranes into industrially applicable spiral- wound membrane modules (SWMM).

[00134] The membrane filtrations showed high flux in various solvents for the three PIM- PEEK membranes. The permeance values for acetonitrile permeation were found to be approximately 10.7 L m ^-2 h ^-1 bar ^-1 for PIM-PEEK-Trip cast from a 26 wt% dope solution tested at 10 bar, 8.7 L m ^-2 h ^-1 bar ^-1 for PIM-PEEK-TB cast from a 19 wt% dope solution tested at 10 bar, 7.4 L m ^-2 h ^-1 bar ^-1 for PIM-PEEK-SBI cast from a 27 wt% dope solution tested at 10 bar. The permeance values for hexane permeation were found to be approximately 4.9 L m ^-2 h ^-1 bar ^-1 for PIM-PEEK-Trip cast from a 26 wt% dope solution tested at 30 bar, 4 L m ^-2 h ^-1 bar ^-1 for PIM-PEEK-TB cast from a 19 wt% dope solution tested at 30 bar, 3.36 L m ^-2 h ^-1 bar ^-1 for PIM- PEEK-SBI cast from a 27 wt% dope solution tested at 30 bar. The membranes showed stable performance during continuous operation in a cross-flow nanofiltration rig over long term with flux values at 30 bar as follows: 248.8 (day 2), 246.9 (day 2), 247.7 (day 3), 247.4 (day 4), 247.5 (day 5), 246.9 (day 6), 246.2 (day 7) L m ^-2 h ^-1 for PIM-PEEK-Trip cast from a 34 wt% dope solution; 228.2 (day 2), 226 (day 2), 224.2 (day 3), 222.8 (day 4), 222.4 (day 5), 220.2 (day 6), 209.4 (day 7) L m ^-2 h ^-1 for PIM-PEEK-TB cast from a 27 wt% dope solution; 107.7 (day 1), 106.9 (day 2), 106.95 (day 3), 106.8 (day 4), 106.55 (day 5), 106.65 (day 6), 106.0 (day 7) L m ^-2 h ^-1 for PIM-PEEK-SBI from a 35 wt% dope solution. The molecular weight cutoff for the membranes, using styrene oligomers, were found to be approximately 530 g mol ^-1 for PIM-PEEK-Trip cast from a 34 wt% dope solution, 820 g mol ^-1 for PIM-PEEK-Trip cast from a 26 wt% dope solution, 480 g mol ^-1 for PIM-PEEK-TB cast from a 27 wt% dope solution, 845 g mol ^-1 for PIM-PEEK-TB cast from a 19 wt% dope solution, 450 g mol ^-1 for PIM-PEEK- SBI cast from a 35 wt% dope solution and 770 g mol ^-1 for PIM-PEEK-SBI cast from a 27 wt% dope solution.

Example 5

Surface Engineering of Membranes

[00135] The properties and performance of the membranes disclosed herein were enhanced by surface engineering. In this Example, it was discovered that membranes with honeycomb surfaces may be fabricated by controlling the polymer molecular weight (M _w ). Although the method is general and applicable to the materials disclosed herein, spirobisindane-based intrinsically microporous poly(ether-ether-ketone) (PIM-PEEK-SBI) homopolymers with low and high M _w s were synthesized and used to prepare organic solvent nanofiltration (OSN) membranes to illustrate the discovered methods. The effects of polymer M _w on its physical properties, membrane morphology (e.g., surface patterns), and performance (e.g., OSN performance) were investigated. PIM-PEEK-SBI showed excellent solution processability, high Brunauer-Emmett-Teller (BET) surface area, and remarkable thermal stability. Three mechanically flexible OSN membranes exhibiting honeycomb surfaces with different honeycomb cell sizes were prepared using PIM-PEEK-SBI homopolymers with low M _w S at concentrations of 27-39 wt% in N-methyl-2-pyrrolidone. By contrast, the use of PIM- PEEK-SBI homopolymers with high M _w s yielded membranes with flat surfaces. The M _w cutoffs of the membranes were fine-tuned in the range of 408-772 g mol ^-1 by adjusting the dope solution concentration. Although the M _w cutoffs were unaffected by polymer M _w , the membranes derived from the polymer with low M _w exhibited substantially higher solvent permeance (18%-26%) than that of the high M _w membrane prepared at the same dope solution concentration. Stable performance was demonstrated over seven days of continuous cross-flow filtration and a six-month aging of the membranes. The application of the methods of this Example extend beyond the PIM-PEEK-SBI polymers and thus is generally applicable to the membranes and other polymers of the present disclosure.

[00136] The significant effect of the M _w of the polymer on the corresponding membrane morphology and performance using spirobisindane-based intrinsically porous PEEK (PIM- PEEK-SBI) is described herein. The polymer was synthesized via a nucleophilic aromatic substitution reaction between spirobisindane diol and 4,4'-difluorobenzophenone in equimolar amounts (Scheme 2). Two batches were prepared with different M _w s, i.e., PIM-PEEK-SBI ^l and PIM-PEEK-SBI* corresponding to low and high M _w s, respectively.

[00137] Synthesis of PIM-PEEK-SBI* and PIM-PEEK-SBI ¹ . PIM-PEEK-SBI ^l and PIM- PEEK-SBI* were prepared via a one-step high-temperature aromatic nucleophilic substitution reaction (SNAT) using equimolar amounts of commercially available 4,4'- difluorobenzophenone and dihydroxy SBI in DMAc in the presence of K2CO3. 4,4'- difluorobenzophenone (1.4 g, 6.5 mmol) and SBI (2 g, 6.5 mmol) were added to a two-necked 200-ml round-bottom flask equipped with a Dean-Stark apparatus in a nitrogen atmosphere. The reagents were dissolved in anhydrous DMAc (15 ml) and anhydrous toluene (4/1 (v/v): DMAc/toluene) followed by the addition of 1.2 equivalents of K2CO3 (1.1 g, 7.8 mmol). Thereafter, the reaction was heated to 140 °C and retained for few hours to allow azeotropic distillation to remove water. The reaction was then heated to 165 °C and maintained for approximately 12 and 16 h to obtain PIM-PEEK-SBI ^l and PIM-PEEK-SBI*, respectively. The reaction medium was then diluted with 10-ml DMAc and poured in distilled water and stirred for 10 h. The diluted medium was filtered and refluxed for 24 h with water and for further 24 h with methanol before drying in a vacuum oven at 180 °C for 24 h to obtain white fibers as the final product.

[00138] PIM-PEEK-SBI* (3.05 g, yield = 94%). ¹ H NMR (500 MHz, CDCl3, δ ): 1.36 (s, 6H), 1.37 (s, 6H), 2.25-2.28 (d, 2H, J = 15 Hz), 2.39-2.42 (d, 2H, J = 15 Hz), 6.55 (d, 2H, J = 2.2 Hz), 6.88 (dd, 2H, J = 6.8 Hz), 6.93 (d, 4H, J = 8.54 Hz), 7.13 (d, 2H, J = 8.3 Hz), 7.70 (d, 4H, J = 8.7 Hz). ¹³ C NMR (125 MHz, CDCb, δ): 30.2, 31.7, 43.1, 57.5, 59.5, 115.8, 116.5, 119.1, 123.1, 131.8, 132.1, 148.4, 152.2, 154.7, 161.6, 194. Fourier-transform infrared (FTIR) (v, cm ^™1 ): 2900-3000 (C-H, str), 1650 (C=0 asym, str), 1600 (C=0 sym, str), 1228 (C-O, str). Number average molecular weight (Mn) = 42,000 g mol ^™1 ; polydispersity index (PDI) = 2.96; SBET = 205 m ² g ^™1 ; thermal gravimetric analysis (TGA): Td,5% = 494 °C.

[00139] PIM-PEEK-SBI ^l (3 g, yield = 93%). ¹ H NMR (500 MHz, CDCb, δ): 1.39 (s, 6H), 1.40 (s, 6H), 2.3 (d, 2H, J = 10.2 Hz), 2.43 (d, 2H, J = 10.2 Hz), 6.59 (s, 2H, J = 2.2 Hz), 6.91- 6.93 (dd, 2H, J=8.2 Hz), 6.96 (d, 4H, J = 8.55 Hz), 7.16 (d, 2H, J = 8.2 Hz). ¹³ C NMR (100 MHz, CDCb, 5): 30.2, 31.6, 43.1, 57.5, 59.6, 116, 116.7, 119, 123, 132, 132.1, 148.4, 152.1, 155, 161.6., 196 FT-IR (v, cm ^"1 ): 2950-3000 (C-H, str), 1660 (C=0 asym, str), 1590 (C=0 sym, str), 1231 (C-O, str). M _n = 19,000 g mol ^-1 ; PDI = 2.1; SBET = 200 m ² g ^-1 ; TGA analysis: Td,5% = 404 °C.

[00140] Membrane fabrication. PIM-PEEK-SBI polymers with low and high M _w s were dissolved at different concentrations (Table 1) in iV-methyl-2-pyrrolidone using an IKA ^® RW 20 digital overhead mechanical stirrer at 22 °C (FIG. 1). Each dope solution was stirred for 24 h to ensure complete dissolution. Thereafter, they were placed in an IKA ^® KS 4000 incubator shaker for 24 h at 25 °C to degas the solution. Each dope solution was then poured onto a Novatexx 2471 polypropylene nonwoven support (Freudenberg Filtration Technologies, Germany). A film was cast using an Elcometer 3700 blade film applicator (Elcometer 4340 Automatic Film Applicator) set at 250-μm thickness with a transverse speed of 150 m h ^-1 . The room temperature and relative humidity were 22 °C and 57% ± 1%. The membrane was immediately phase inverted by immersing in deionized (DI) Type Π water (Milli-Q) with a resistivity of 18.2 ΜΩ cm. The DI water in the bath was changed three times. To prevent any bacterial growth, the membranes were stored in DI water with 1 vol% acetonitrile.

[00141] Four membranes were investigated in this study: M0, which was an open membrane prepared using PIM-PEEK-SBI*, and Ml, M2, and M3, which corresponded to open, ajar, and tight membranes prepared using PIM-PEEK-SBI ¹ , respectively (Table 1).

Table 1. Membrane designations. The viscosity and concentration of each of the four polymer dope solutions yielding a flat-surface membrane (M0) or a honeycomb-surface membrane (Ml, open; M2, ajar, M3, tight), and the density of each membrane.

[00142] Characterization and Methods. ¹ H and ¹³ C NMR spectra of the SBI monomer and

PIM-PEEK-SBI polymers (recorded in ppm) were obtained using a Broker AVANCE-ΙΠ spectrometer at frequencies of 400 and 500 MHz in either deuterated chloroform (CDCb) or DMSO-d6. The M _w , M _n , and PDI of PIM-PEEK-SBI* and PIM-PEEK-SBI ¹ were obtained via gel permeation chromatography (GPC) (Agilent 1260 infinity multi-detector GPC/SEC) using tetrahydrofuran (THF) and polystyrene as the solvent and external standard, respectively. FT- IR spectra of the polymers were acquired using diamond attenuated total reflection on a Varian 670-IR FT-IR spectrometer.

[00143] TGA was performed (TA Instruments, Model QS000) to evaluate the thermal decomposition temperature of each polymer. All analyses entailed a drying step at 100 °C for 30 min, which was further increased to 700 °C at a ramp rate of 5 °C min ^-1 . Differential scanning calorimetry (DSC; TA Instruments, Model Q2000) was performed at 400 °C with a ramp rate of 5 °C min ^-1 to obtain the glass transition temperature of each PIM-PEEK-SBI polymer. To measure the <i- spacing between adjacent polymer chains, wide-angle X-ray scattering experiments were conducted on a B raker D8 Advance diffractometer from 8° to 50° with a scanning rate of 0.5° min ^-1 . The density of polymers and membranes were measured using a Mettler Toledo balance (XPE204) equipped with a density kit based on the Buoyancy method using iso-octane as a reference liquid.

[00144] Surface and cross-sectional images of the membranes were collected using a scanning electron microscope (SEM; Merlin, ZEISS), which was operated at 5 kV with a 5- mm working distance. For cross-sectional image analysis, the samples were prepared by fracturing the frozen membranes in liquid nitrogen. All membranes were sputter-coated with 5-nm iridium. Each dried membrane was fixed on a glass slide using a double-sided tape for surface morphology analysis. The Feret diameter distribution was obtained for each honeycomb surface through the SEM surface image using ImageJ software (vl.52a). An 8-bit image type was selected, an image threshold was imposed to identify the honeycomb shapes and analyze the surface patterns. The mean Feret diameter was obtained, which was used to plot the context of a diameter histogram.

[00145] The surface roughness of each PIM-PEEK-SBI membrane was measured using an atomic force microscope (AFM; Agilent 5500) and calculated as an average based on four scans; the corresponding 5 x 5 pm images are shown in FIGS.3M-3P. The water contact angle (WCA) of each membrane was measured by the sessile drop method using a drop shape analyzer (Easy drop, KRUSS) equipped with a video camera. The average value of each sample was obtained based on at least five measurements per sample. Nitrogen and carbon dioxide adsorption isotherms of the powder sample of each polymer were obtained using a Micrometries ASAP 2050 surface area and porosimetry analyzer. After degassing each sample at 180 °C for 12 h at a pressure below 10-μm Hg, nitrogen and carbon dioxide adsorption isotherms were achieved at -198 °C up to 1 bar and 0 °C up to 10 bar, respectively. The apparent Brunauer-Emmett-Teller (BET) surface area was calculated from nitrogen and carbon dioxide adsorption data using multipoint BET analysis. BET surface areas in both carbon dioxide and nitrogen were calculated from the linear isotherm plot over a relative pressure range of 0.05-0.30. The swelling of the membranes was calculated based on Equation 1, using membrane thickness soaked in pure water and organic solvents over 48 h.

[00146] The mechanical properties of each PIM-PEEK-SBI membrane were obtained using a Nano Test Vantage instrument. The dried membranes were fixed on a silicon wafer surface. To confirm the obtained results, the test was performed three times for each membrane. [00147] Membrane filtration experiments . The separation performance of the PIM-PEEK-

SBI membranes was tested using a typical cross-flow nanofiltration apparatus. A microannular gear pump, i.e., a recirculation pump (Michael Smith Engineers Ltd., GD-M35JF5S6 ATEX), was used to ensure a homogeneous concentration in the retentate loop and mitigate the concentration polarization at the membrane surface. The retentate was recirculated at 1.2 L min ^-1 . Each membrane was washed with and soaked in acetonitrile, followed by conditioning under an applied pressure of 30 bar for 24 h before evaluating the membrane performance. Once the system reached a steady state, the rejection value and flux were measured. The flux was determined by measuring the volume of the solvent permeating through the membrane (V) in a given time (t) for a given membrane surface area (A). The flux and permeance were calculated using Equations 2 and 3, respectively.

[00148] The active membrane area was 52 cm ² . The solute rejection value (Eq. 4) was obtained from the ratio of the permeate (c _permeate ) and retentate (c _retentate ) concentrations of the solutes. Standard polystyrene markers containing 1-g L ^-1 PS580 and PS 1300 and 0.1-g L ^-1 methyl styrene dimer (236 g mol ^-1 ) were used for filtration. The molecular weight cutoff (MWCO) is defined as the lowest M _w solute exhibiting 90% retention by the membrane. MWCO was estimated using linear interpolation from the rejection profiles. Standard deviations were reported on the basis of two independent measurements performed on independently prepared membranes from independently prepared polymer batches.

[00149] Polymer synthesis and characterization. PIM-PEEK-SBI* was prepared via a one- step high-temperature aromatic nucleophilic substitution reaction (SNAT) between equimolar amounts of 4,4'-difluorobenzophenone and dihydroxy SBI in anhydrous DMAc in the presence of anhydrous K2CO3 at 165 °C (Scheme 2) for 16 h. PIM-PEEK-SBI ^l was prepared using the same conditions; however, the reaction time was reduced to 12 h. Scheme 2 shows synthetic routes for PIM-PEEK-SBI polymers with low (PIM-PEEK-SBI ^l ) and high (PIM-PEEK-SBI*) molecular weights. ¹ H and ¹³ C NMR spectra confirmed the exact chemical structure of each polymer (FIG. 2A). In addition to NMR, FTIR spectroscopy was employed to detect the characteristic absorption bands of PIM-PEEK-SBI* and PIM-PEEK-SBI ^l (FIG. 2B), confirming the formation of the same polymer in both cases without any structural differences. The ether linkage was identified at 1231 cm ^-1 (C-O, str), while the keto group was identified at 1656 cm ^-1 (C=0 asym, str) and 1590 cm ^-1 (C=0 sym, str).

[00150] The only difference between the two polymers was the M _w . The 12-h reaction time yielded a polymer with a low M _w , i.e., PIM-PEEK-SBI ^l , as confirmed by the GPC results using polystyrene and THE as the eluent and external standard, respectively. The elution time of PIM-PEEK-SBI* was approximately 1 min less than that of PIM-PEEK-SBI ^l (FIG.2C); this difference explains the higher M _w of the former (Table 2). PIM-PEEK-SBI* and PIM-PEEK- SBI ¹ exhibited Mn values of 42,000 and 19,000 g mol ^-1 and PDI values of 2.97 and 2.1, respectively.

[00151] TGA demonstrated the effect of M _w on polymer stability. For instance, the 5% decomposition temperature decreased from 494 °C (PIM-PEEK-SBI*) to 404 °C (PIM-PEEK- SBI ¹ ) when M _n was decreased from 42,000 to 19,000 g mol ^-1 (FIG. 2D). The effect of M _w on polymer degradation has been previously reported for other types of polymers, in which polymers with lower M _w s exhibited lower decomposition temperatures. For example, intrinsically microporous 6FDA-TrMPD polyimide demonstrated different decomposition temperatures for different M _w s, wherein polymers with lower M _w s exhibited lower decomposition temperatures and vice versa.

[00152] In line with literature observations, the glass transition temperature (T _g ) of the polymer depends on polymer size, chain flexibility, and M _w [28,29]. Therefore, for a particular polymer, T _g increases with an increase in M _w and vice versa. PIM-PEEK-SBI* displayed a higher T _g (242 °C) than PIM-PEEK-SBI ^l (201 °C) (Table 2, FIG. 2E). Moreover, the effect of M _w on the physical properties of the polymer was also observed for density, where PIM-PEEK- SBI* displayed higher density relative to PIM-PEEK-SBI ^l .

Table 2. Physical properties of PIM-PEEK-SBI with high and low molecular weights.

° Measured using 1260 Agilent gel permeation chromatography with polystyrene as the calibration standard and tetrahydrofuran as a solvent; ^b Measured using thermal gravimetric analysis up to 700 °C with a ramp rate of 5 °C min ^-1 ; ^c Measured using differential scanning calorimetry with a ramp rate of 5 °C min ^-1 . ^d Measured using Mettler Toledo density kit in iso-octane.

[00153] Despite the significant difference in the M _w , PIM-PEEK-SBI* and PIM-PEEK- SBI ¹ demonstrated the same solubility in organic solvents. Both polymers were subjected to solubility tests in 40 different solvents using Hildebrand solubility parameters (HSP) between 5 and 45 MPa ^0-5 . The two polymers were soluble in some solvents with HSP between 17 and 25 MPa ^0-5 and dielectric constant (DC) between 0 and 40. Contrarily, both polymers were insoluble in solvents with HSP below 17 or higher than 25 and DC over 40 (FIG. 2F). In addition to conventional solvents, 16 environmentally friendly (green) solvents were examined to promote their use in subsequent process development using the membranes disclosed herein. [00154] Moreover, XRD results showed no significant difference between polymers with low and high M _w s. PIM-PEEK-SBI* and PIM-PEEK-SBI ^l exhibited major peaks at 2Θ of 17.7° and 18.1°, respectively. These findings reconfirmed that no structural differences were observed between polymers with low and high M _w s. Consistently, the BET surface area derived from carbon dioxide for each batch was nearly indistinguishable within a systematic error, with BET surface areas of 205 and 200 m ² g ^-1 for PIM-PEEK-SBI* and PIM-PEEK-SBI ^l , respectively. The BET surface area of PIM-PEEK-SBI ^l was also measured for nitrogen gas at -196 °C, revealing a value only one-third of that revealed by carbon dioxide. This difference in the results is attributed to the size difference between nitrogen carbon dioxide. Carbon dioxide, with its smaller size, can penetrate through the material and enter the smallest pores, which nitrogen cannot reach.

PIM-PEEK prepared with different reaction times resulted in different polymer molecular weights which showed a promising method to engineer the membrane surface and tailor it is performance. PIM-PEEK-SBI with Mn = 42 kg mol ^-1 resulted in flat surface morphology, while PIM-PEEK-SBI with Mn=20 kg mol ^-1 , resulted in honeycomb morphology. Molecular weight can vary from 1 kg mol-1 to 1000 kg mol-1 and the polymer dope solution concentration can be varied from 1% to 99%.

[00155] Membrane Morphology. FIGS. 3A-3P shows the surface and cross-sectional morphology through SEM images and surface topology through AFM images of the PIM- PEEK-SBI membranes (M0-M3). M0 prepared using PIM-PEEK-SBI* revealed a flat-surface morphology. Alternatively, the other three membranes fabricated using PIM-PEEK-SBI ^l (M1- MS) exhibited a honeycomb-surface morphology with microsized patterns. The higher M _w of the polymer resulted in the formation of a flat surface. The size of the honeycomb pattern was controlled by the concentration of the dope solution. Tighter and uniform pores were observed when the concentration of the dope solution was increased. M3 demonstrated a distinct honeycomb surface with a pore size in the range of 0.6-0.8 μm, while Ml exhibited a porous surface with a wider range of pore sizes in the range of 1.5-12.0 pm (FIGS. 3A-3H, Table 3). The Ml honeycomb membrane exhibited approx. 18% lower density compared to the M0 flat membrane (Table 1). Moreover, the density of membranes Ml to M3 increased from 0.688 to 0.892 g cm ^""3 with increasing dope solution concentration. The obtained density values correlate with the cross-sectional images, showing that the pores and macrovoids (FIGS. 3J-3L) in the honeycomb membranes result in materials that are less dense than the flat membranes.

[00156] Moreover, the cross-sectional images of M1-M3 revealed a sponge-like structure (FIGS. 3J-3L) and those of M0 revealed a common finger-shaped macrovoid structure as a result of phase inversion (FIG. 31). Pores on the surface are generally formed by the condensation of water vapor on the surface during solvent evaporation. Higher viscosity of the dope solution is beneficial for the delay of droplet growth on the surface and is likely to accelerate the solidification rate during the phase inversion process, resulting in the formation of smaller pores at a high concentration. The honeycomb-surface morphology was also observed in the AFM image of M3 using 5 x 5-μιη image scanning (FIG. 3P). Thus, variations in the polymer M _w had a significant impact on the cross-sectional morphology and surface pattern of the membranes.

[00157] The thickness of the polymer layer on the non-woven support was determined from SEM cross-sectional images of the membranes, which increased from 90 to 130 pm with an increase in the dope solution concentration (Table 3). Thick membranes were obtained at a high concentration (M1-M3) owing to the delayed demixing rate between the solvent and water. The membrane (107 pm) fabricated using PIM-PEEK-SBI ^h (M0) was thicker than the corresponding honeycomb membrane prepared using PIM-PEEK-SBI ^l (90 pm).

Table 3. Membrane thickness, honeycomb dimensions, and surface properties, n. a. = not applicable.

[00158] Variations in M _w can have a considerable impact on the membrane mechanical properties and flexibility and can yield reduced modulus. For instance, robust and stable membranes can be obtained using polymers with high M _w , while polymers with low M _w produce brittle membranes. Nanoindentation analysis revealed that the Ml membrane prepared using PIM-PEEK-SBI ^l demonstrated a reduced modulus of 0.11 GPa. This value is a quarter of that of the M0 membrane (0.513 GPa) with similar hardness, which is prepared using PIM- PEEK-SBI ^h (Table 3). The reduced modulus and hardness of the membranes improved with increasing dope solution concentrations (Tables 1 and 3). From a practical viewpoint, membranes were sufficiently strong for use in OSN at pressures up to 30 bar. The AFM images were used to evaluate the surface roughness of the membranes. The surface roughness of Ml was 18.47 nm, which was nearly twice that of the corresponding flat-surface membrane (M0). M3 exhibited the highest surface roughness of 556 nm in this series and showed a honeycomb- patterned surface, thereby explaining its high roughness. Moreover, Ml revealed a slightly higher WCA than MO; this difference was attributable to the higher surface roughness of Ml based on the Wenzel equation model. WCA remained constant with an increase in dope solution concentrations (Table 3, FIGS. 3E-3F).

[00159] Furthermore, the Feret diameter distributions of the honeycomb surfaces were obtained from the SEM surface images of the membrane using Image! software (FIG. 4). Ml and M2 revealed a broad diameter distribution with a range of 1.5-12 pm, with the maximum intensity at approximately 6 pm. M2 demonstrated a slightly sharper peak than Ml, indicating a more uniform and tighter honeycomb diameter size in M2 than in Ml, as clearly observed in the SEM images (FIGS. 3A-3L). Moreover, M3 displayed a very sharp peak in the range of 0.6-0.8 pm, indicating the formation of a highly uniform honeycomb at the membrane surface (Table 3).

[00160] Membrane Performance. The MWCO values of the PIM-PEEK-SBI ^l membranes (Ml -M3) were determined in acetonitrile at 30 bar and compared with those of the control membrane (M0) (FIG. 5A). As the dope solution concentration increased, the MWCO and permeance decreased owing to the formation of tighter membranes. In the case of PIM-PEEK- SBI ^l , when the dope solution concentration was increased from 27 to 39 wt%, MWCO decreased from 772 to 408 g mol ^-1 and acetonitrile permeance from 9.82 to 3.15 L m ^-2 IT ¹ bar ^-1 , respectively. Pore diameter analysis (FIG. SB), which was obtained from the pore flow model using styrene rejection values, showed good correlation with the MWCO values, and revealed that the pore diameters of M1-M3 were 0.86, 0.46, and 0.44 nm, respectively. Thus, the tightest membrane, M3, exhibited a lower MWCO and pore size diameter, whereas a higher MWCO and pore diameter were observed for Ml. The pore diameter value (0.84 nm) and MWCO (770 g mol ^-1 ) of the control membrane (M0) were similar to those of M 1. The rejection profiles of M0 and Ml were similar at over 700 g mol ^-1 . However, below 700 g mol ^-1 , rejection became more prominent. For instance, at 236 g mol ^-1 , Ml showed 13% greater rejection than M0. Three dyes and five active pharmaceutical ingredients (APIs) were filtered using M0 and Ml in acetonitrile at 30 bar (FIG. 5C). With its honeycomb-patterned surface, the Ml membrane exhibited an MWCO of approximately 500 g mol ^-1 , which is approximately 23% lower than that of flat-surfaced M0. These results suggest that the honeycomb pattern surface can induce subtle changes in the OSN performance. The polystyrene marker showed approx. 770 g mol ^-1 MWCO (FIG. 5A), while the nanofiltration with dyes and APIs revealed a lower MWCO in the range of 500-600 g mol ^-1 (FIG. 5C)

[00161] The M1-M3 membranes were tested in acetonitrile at 10, 20, and 30 bar, showing a linear increase in flux as the pressure increased. M0 exhibited lower flux at all tested pressures than Ml (FIG. 5D). To further investigate the OSN performance, five solvents with varying polarities were tested at 30 bars (FIG. 5E). The permeance of MO and Ml was directly correlated with the binding energy between the solvent and polymer chains, as calculated via molecular dynamic simulations. The solvent permeance linearly increased as the absolute value of the binding energy between the solvent and polymer increased (FIG. 5E). The highest degrees of interaction between polymer chains and solvent molecules were found for polar solvents such as acetone and acetonitrile. The least polar solvent, i.e., hexane, showed the lowest binding energy and permeance. Ml, which was prepared using PIM-PEEK-SBI ^l , exhibited higher permeance for all solvents than MO, which was fabricated using PIM-PEEK- SBl\ Ml showed a 18% higher hexane (nonpolar) permeance of 3.97 L m ^-2 h ^-1 bar ^-1 than MO. Moreover, the acetonitrile (polar) permeance of Ml was 9.82 L m ^-2 h ^-1 bar ^-1 , which was 26% higher than that of MO. These examples demonstrate that the increase in permeance (Ml versus MO) became more prominent with an increase in solvent polarity and binding energy (FIG. 6E). The swelling of the membranes decreased with decreasing membrane-solvent interactions

(FIG. 5F). The tighter the membrane (Ml — > M3), the lower the swelling of the material. Ml and M3 exhibited swelling up to 9.9% and 2.3%, respectively.

[00162] FIG. 5G shows a performance comparison between PIM-PEEK-SBI ^l and PIM-

PEEK-SBI* membranes, as well as a sulfonated PEEK (SPEEK) membrane. PIM-PEEK-SBI ^l membranes showed higher acetonitrile permeance and styrene dimer rejection than PIM- PEEK-SBI*. Moreover, compared with conventional SPEEK, M2 and M3 demonstrated higher permeance values of 240% and 60% without compromising the rejection value. In other words, both M2 and M3 exhibited higher permeance and rejection than conventional SPEEK.

[00163] During the initial 24 h of filtration, the flux values of both M0 and M 1 membranes decreased until they reached the steady state. However, the decreasing flux behavior differed for the two membranes; M0 showed a 13% flux reduction (from 270 to 235 L m ^-2 h ^-1 ), and Ml showed a 27% flux reduction (from 409 to 279 L m ^-2 h ^-1 ) (FIG. 6A). This difference in flux reduction could be attributed to the difference in membrane morphology at a macroscopic level. [00164] Moreover, the styrene dimer (M _w = 236 g mol ^-1 ) rejection value increased by 5% and 7% for Ml and M0, respectively (FIG. 6A). Membrane stability was tested over seven days of continuous filtration (FIG. 6B). Ml demonstrated constant flux and rejection performance over seven days. The membranes were subjected to aging in acetonitrile over a six-month period, followed by seven days of continuous filtration (FIG. 6B). The results indicate that Ml showed negligible aging, which was consistent with a previous report for SPEEK.

[00165] M _w effects on polymer properties, membrane morphology, and OSN performance were systematically investigated using PIM-PEEK-SBI polymers with low and high M _w s. Polymer thermal stability and mechanical properties deteriorated at a low M _w . The membrane fabricated using a polymer with a high M _w exhibited a flat surface, while the low M _w counterparts exhibited honeycomb-patterned surface. The surface patterns (flat versus honeycomb) of the PIM-PEEK-SBI membranes did not affect the MWCO, however the permeance increased from 7.8 to 9.8 L m ^-2 IT ¹ bar ^-1 with the introduction of the honeycomb surface. The increase in the dope solution concentration afforded increasingly uniform honeycomb patterns with a Feret diameter as low as 0.6 pm. Higher flux and rejection values were obtained for the honeycomb membranes prepared using low M _w PIM-PEEK-SBI than those for the flat membranes fabricated using high M _w PIM-PEEK-SBI. The honeycomb membrane demonstrated steady-state performance during seven days of continuous nanofiltration in acetonitrile at 30 bar. A six-month aging of the membrane did not affect the membrane performance. The findings of this research present new opportunities to modify membrane surfaces and performance by varying the M _w s of polymers.

Example 6

Surface Engineering of PIM-PEEK-SBI Membranes

[00166] Hybrid PEEK polymers were (e.g., PIM-PEEK) prepared with different reaction times resulting in different polymer molecular weights which allowed engineering of the membrane surface and tailoring of its performance. PIM-PEEK-SBI with M _n = 42 kg mol ^" 1 resulted in flat surface morphology, while PIM-PEEK-SBI with M _n =20 kg mol ^-1 , resulted in honeycomb morphology. See FIGS. 7A-7B which show SEM images of a PIM-PEEK-SBI (low molecular weight) membrane showing the surface morphology of said membrane, according to one or more embodiments of the invention. Molecular weight can vary from 1 kg mol ^-1 to 1000 kg mol ^-1 and the polymer dope solution concentration can be varied from 1% to 99%. In general, polyether ether ketones with polymer backbones into which polymers of intrinsic microporosity have been incorporated are referred to herein as PIM-PEEK or PIM- PEEK polymers (or generally as hybrid PEEK polymers).

[00167] Low molecular weight PIM-PEEK-SBI Preparation: PIM-PEEK-SBI with low molecular weight was prepared by nucleophilic aromatic substitution reaction (SNA _T ) by reacting a dihydroxyl spirobisindane with a 4,4’ -difluorobenzophenone in an equimolar amount in DMAc at 165 °C for 12 hours. The obtained polymer fibers were treated and washed with hot water and methanol for few time and dried at 180 °C in the vacuum oven for 24 hours.

The resulting PIM-PEEK-SBI had a BET surface area of 200 m ² g ^-1 and a 5% decomposition temperature of 404 °C. PIM-PEEK-SBI was found to be soluble in N-Methyl-2-pyrrolidone (NMP), Dimethylacetamide (DMAc), Cyrene and tetrahydrofuran (THF).

[00168] Honeycomb membranes preparation. Dope solutions with different concentrations were prepared from the PIM-PEEK-SBI with low molecular weight and used to prepare integrally skinned asymmetric (ISA) membranes by phase inversion method. N- Methyl-2-pyrrolidone (NMP) was used as the solvent to prepare a dope solution from the PIM- PEEK-SBI polymers, and water as a non-solvent for the coagulation bath. The obtained membranes demonstrated good flexibility and mechanical stability, which allowed their scale- up and the rolling of the flat sheet membranes into industrially applicable spiral-wound membrane modules (SWMM). The membrane prepared from dope solution concentration of 27 wt% demonstrated honeycomb surface with honeycomb diameter of 1.5-12.0 pm, honeycomb depth of 1.51 pm and surface roughness of 18.47 nm. The honeycomb membrane prepared from dope solution concertation of 33% resulted in honeycomb diameter of 3.0-9.0 pm, honeycomb depth 1.41 pm, and surface roughness of 5.41 nm. The honeycomb membrane prepared from dope solution concentration of 39% resulted in honeycomb diameter of 0.6-0.8 pm, honeycomb depth 0.31 pm, and surface roughness of 556 nm.

[00169] Honeycomb membrane performance. Membranes with honeycomb surface displayed high permeance for all tested solvents relative to the membranes with flat surface with same dope solution concentration (27 wt%). For instance, the permeance of acetonitrile was 7.81 ± 0.25 and 9.82 ± 0.37 L m ^'2 h ^'1 bar ^-1 for flat and honeycomb membranes, respectively. The flux values for hexane permeation were found to be approximately 101 and 119 L m ^-2 h ^-1 for PIM-PEEK-SBI with flat and honeycomb surface, respectively, cast from a 27 wt% dope solution tested at 30 bar.

[00170] The honeycomb membrane, prepared from 27 wt% dope solution of low molecular weight PIM-PEEK-SBI, showed stable performance during continuous operation in a cross-flow nanofiltration rig over long term for fresh and aged membrane with flux values at 30 bar as follows: for fresh membrane, 298 (day 1), 296 (day 2), 295 (day 3), 293.6 (day 4), 293.25 (day 5), 293.75 (day 6), 293 (day 7) L m ^-2 h ^-1 . For six-month aged membrane, 275.6 (day 1), 275.9 (day 2), 289.75 (day 3), 297.2 (day 4), 285.95 (day 5), 285.35 (day 6), 288.45 (day 7) L m ^-2 h ^-1 . [00171] The hybrid PEEK polymer membranes with honeycomb morphology are advantageously insoluble in a number of organic solvents. In some embodiments, the hybrid PEEK polymer membranes are insoluble in acetonitrile, hexane, dimethylformamide (DMF), tetrahydrofuran (THE) and the like. Accordingly, a wide array of organic feed streams and operational temperatures can be used in nanofiltration utilizing the hybrid PEEK polymer membranes of the present invention.

[00172] PIM-PEEK polymers also showed great potential for dyes and active pharmaceutical ingredients (APIs) removal. For instance, PIM-PEEK-Trip (34%) with flat surface demonstrated dyes permeance in acetonitrile as following: 4.995 L m ^'2 h ^'1 bar ^-1 (Estradiol), 5.195 L m ^-2 h ^-1 bar ^-1 (Methyl orange), 5.035 L m ^-2 h ^-1 bar ^-1 (Losartan), L m ^-2 h ^-1 bar ^-1 5.155 L m ^-2 h ^-1 bar ^-1 (Valsartan), 5.045 L m ^-2 h ^-1 bar ^-1 (Oleuropein), 5.115 L m ^-2 h ^-1 bar ^-1 (Acid fuchsin), 4.965 L m ^-2 h ^-1 bar ^-1 (Roxithromycin), and 4.98 L m ^-2 h ^-1 bar ^-1 (Rose Bengal). The rejection of these dyes was as following: 76.5% (Estradiol), 75.65% (Methyl orange), 87.05% (Losartan), 84.75% (Valsartan), 97% (Oleuropein), 99% (Acid fuchsin), 99.6% (Roxithromycin), and 99.75% (Rose Bengal).For PIM-PEEK-SBI with honeycomb surface demonstrated MWCO of approximately 500 g mol ^-1 resulted from testing three dyes and five APIs, which around 23% lower than the PIM-PEEK-SBI with flat surface.