The invention relates to a process or method for inserting or dispersing quartz inside a substrate preferably containing polarisable polymers. The invention also relates to the substrate obtained.

In other patent applications, hereto referred to, the applicant described a polarisable substrate or paint, for example by means of laser, which quartz is dispersed in so as to also confer piezoelectric properties to the paint.

When subjected to an external force the quartz is able to generate an electric signal (voltage and current) which by means of conductive paths made in the paint is propagated where desired. The quartz itself can apply a force to the paint if electrically powered with opportune impulses via the aforementioned paths.

The problem remains of how to conveniently insert the quartz in the paint to achieve the desired effects.

The invention sets out to overcome this problem by the method defined in claim 1.

It is advantageous to disperse in a matrix or substrate, preferably of solvent, sintered material containing quartz, known as "loaded quartz", in other words provided with micro-electrodes, preferably metallic, to collect or send electric charges. A process for loading quartz involves sublimating two conductor sheets above and below a layer of quartz at high temperature (about 700°C), sintering it at 1000°C and then cooling to about 200°C to then expose it to an electric field of about 3000V/ cm so as to position all the quartz particles with the electrodes parallel and alongside each other. A sandwich structure of oriented quartz placed between two conductor sheets results.

According to the inventive concept, such sandwich is ground to form small particles of quartz P (see Fig. 1) as desired which each have two electrodes E. The particles P are then dispersed in the substrate.

Another problem is the orientation of the particles of loaded quartz. See

Fig. 1 which shows the particles of oriented quartz compared. Especially when the quartz generates charge impulses following a charging or pulsating force, the maximum energy yield is only achieved if the quartz is oriented parallel to the direction of the pulsating force. That is to say that the micro-electrodes of each particle of quartz should align with the line of action of the force, so as to receive the maximum component. In addition, each application may require different orientations. For example, if the charging force is a vehicle and the substrate is laid on the road, it is clear that the quartzes should preferably be inclined in relation to the orthogonal of the road surface, towards the oncoming vehicle, only so is the component resulting from the movement impressed on the substrate exploited.

The sintering method described above may at most produce (see Fig.l left) quartz Q dispersed in a substrate 10 which has two electrodes E the axis X of which is oriented substantially orthogonal to the main surface S of the substrate 10 (parallel to the line H orthogonal to S).

The invention sets out to overcome this problem by the method as characterised in claim 2. Not only does the use of a magnetic field enable orientation of all the particles Qinv (see Fig.l to the right) in whatever direction desired (Y axis), but this happens even at very low temperatures, e.g. max 150°C, at which the substrate is still in a gelatinous form and not dry, and does not risk deterioration as a result of the high temperature. The prior art rather, applying an electric field to a solid sandwich and not a fluid substrate, requires heating of the material to a high temperature, with consequent deterioration problems. The axis X of the Qinv particles can be oriented at will simply by directing the magnetic field in the desired direction. The Qinv particles are floating in the substrate 10 yet to solidify and rotate to orient themselves without much opposition.

It is, anyway, possible to use both the methods expounded above, either separately or combined.

An alternate magnetic field generated for example with an inductor coil, at frequencies for example to the order of KHz, is more advantageous because it periodically induces an orienting momentum on the particles and, period after period, succeeds in orienting the quartz without stress on the material.

To definitively stabilise the configuration of the particles of loaded quartz, one simple and efficacious way is to expose the substrate to UV radiation. As UV the general type used, for example to dry paints, may be used.

The substrate which contains all the elements which we will describe below in dispersion may generically be a solvent, preferably aromatic. In particular use of a benzene is preferred, and preferably a dichlorobenzene (because it dissolves the Thiophene well), a dichloromethane or a nitro type thinner.

As well as metal oxides in the substrate there may be a further component for example such as a graphite. Graphites are excellent dopants, mainly because of their high electric conductivity. Particular sub-families of the graphites which have proven most advantageous, since the said qualities are accentuated, are fullerene and graphene.

The metal oxides may be:

- freely dispersed in a random manner inside a matrix of, for example, vinyl-acetate or vinyl -ester paint, or

- also dispersed in a matrix of polymers with conjugated covalent double bond, that is to say heterocyclic compounds, formed of n atoms of carbon and one atom of a different type bound in a ring structure.

One advantageous family of these polymers is Butadiene, which has a very stable molecule.

Another advantageous family of polymers is Thiophene or polythiophene, which substitutes vinyl. The molecules of Thiophene have the marked characteristic, as will be seen later, of positioning themselves in a laminar mode, that is to say all over a plane without overlapping. In addition the sulphur atom of Thiophene has many electronic affinities with the matrix. In fact Thiophene has a free atom of Sulphur which acts as a binding agent of the monometric chains during polymerisation.

Thiophene and Butadiene can also be mixed together in the matrix.

The aforesaid polymers and graphites can co-operate together in the matrix with the metal oxides. Note however that one or more of said polymers may also be used on their own in the matrix without the help of the oxides and/ or in their place (everything described for the rest of the substrate still applying).

Iron chloride or aluminium chloride, with or without colouring pigments, may be added to the metal oxides plus the polymers or when on their own to only one of the two. Such chlorides are strong dopants, and are convenient both because they eliminate a hysteretic phenomenon which will be spoken of below and because they have a marked capacity to release/ accept electrons. In particular the iron chloride or aluminium chloride are oxides dissolved in chlorine which dissolves well in thiophene, which is a plastic. The excellent homogenisation ensures excellent communication at an electronic level, which favours the interchange of electrons towards the polymer (e.g. thiophene).

The metal oxides may, for example, consist of iron oxides in the formulation Fe ₂ 0 ₃ or Fe ₃ 0 ₄ or even better, for an improved magnetisation/ saturation curve, by chrome oxides or dioxides, in the formulation Cr0 ₂ .

The metal oxides, with any graphite, and/ or any polymers will be dispersed in the matrix or substrate of paint.

The mixture of paint may be loaded with the metal oxides, or even with only one or several of said polymers, preferably Thiophene, and as said of the quartz (one or more of its 19 families), in particular BaTi0 ₃ or PbTi0 ₃ . A component with Ti0 ₃ has the advantage of promoting adhesion, not being dry and also being able to make free electrons available with little energy. During the preparation of the structured quartz other products are added so as to encourage the growth of the electrodes and increase, through appropriate doping, the availability of a greater production of charges.

As said, signals or current can be generated in situ on said paint by compressing it with a finger or any element or weight, or other system. Conductor paths are created using a laser ray to get electric signals from the quartz or to power it with the same.

Quartz of a greater particle size may also be used to increase the conductivity of the substrate. However the quartz dispersed in the matrix , in particular thiophenic, may constitute an obstacle to tracing the conductive paths. In fact quartz does not conduct and a path would be interrupted. This problem is overcome by providing a layer of matrix with charged quartz laid over a layer without it. In particular a first substrate composed as described is spread, then a second is spread over the first substrate when it has dried. Said particles of charged quartz are then dispersed in the second substrate, and they are given a specific spatial orientation where necessary. In the end the two layers appear as a single block.