WO2016042248A1

WO2016042248A1 - Substrate made of a construction material, coated with a layer of polymers deposited by plasma technology and a thin film

Info

Publication number: WO2016042248A1
Application number: PCT/FR2015/052458
Authority: WO
Inventors: Matthieu Horgnies; Isabelle Dubois-Brugger
Original assignee: Lafarge
Priority date: 2014-09-15
Filing date: 2015-09-15
Publication date: 2016-03-24
Also published as: FR3025794A1

Abstract

The invention relates to a product (1) comprising: a substrate made of a construction material (2); a composition of polymers (3) arranged over all or part of the surface of the substrate made of a construction material (2), the composition of polymers (3) being deposited by plasma-enhanced chemical vapour deposition; and a thin film (4) for forming all or part of an electronic device, especially operating on the basis of the photovoltaic effect, and arranged over all or part of the composition of polymers (3).

Description

SUBSTRATE OF CONSTRUCTION MATERIAL COATED WITH POLYMER LAYER DEPOSITED BY PLASMA TECHNOLOGY AND

The present invention relates to a product comprising a substrate of construction material, in particular concrete, having at least one surface covered with a layer of polymers itself coated with a thin layer, with a coating method of such a substrate, and an element for the field of construction comprising such a product.

The present invention relates to the technical field of surface treatment of substrates made of construction material, especially concretes.

Cities include many buildings, buildings, structures or infrastructure (including transport) with high surface capacity, which would be relevant to use to produce electricity from renewable energies, especially of solar energy, thanks to the photovoltaic effect. For this purpose, it becomes interesting to use the concrete surfaces available on the many works in the cities. However, the application of prefabricated solar panels on the facades or more generally on concrete surfaces is long and expensive, and requires a lot of manpower. In addition, it requires prior manufacture of solar panels in the factory.

Also the technical problem to be solved by the invention is to provide a building element for the realization of buildings, buildings, structures or infrastructure and comprising on at least a portion of its surface a thin layer for forming all or part of an electronic device, in particular a device operating on the basis of the photovoltaic effect.

Such an electronic device would ultimately produce electricity, without resorting to the use and installation of prefabricated solar panels.

Surprisingly, the inventors have shown that the fact of covering a concrete having a smooth surface, by means of a first layer of polymers deposited by plasma technology makes it possible to deposit on this surface a thin layer that can be used to manufacture an electronic device .

Thus, the invention relates to a product comprising:

a substrate of construction material,

a polymer composition disposed on all or part of the surface of the substrate of construction material,

the polymer composition being deposited by plasma-assisted chemical vapor or gas deposition, and - A thin layer intended to form all or part of an electronic device, in particular operating on the basis of the photovoltaic effect, and disposed on all or part of the polymer composition.

The deposition of the polymer layer makes it possible to obtain on the one hand a surface having a very low intrinsic porosity with a smooth, very little rough and homogeneous surface state, with sizes of surface defects (depth of the streaks and / or asperities heights) less than one micrometer making it possible to promote the adhesion of the thin layer, and on the other hand makes it possible to obtain a uniform and homogeneous deposition of the thin layer.

Advantageously, the thin layer is deposited on all or part of the polymer composition by plasma-assisted chemical vapor or gas deposition.

According to one aspect of the invention, the building material is a concrete.

The concrete used may be a structural concrete, that is to say preferably having performance in accordance with the NF EN 1992-1 -1 standard of October 2005.

By the term "concrete" is meant a mixture of hydraulic binder (for example cement), aggregates, water, optionally adjuvants, and possibly mineral additives, such as for example high performance concrete, Ultra-high performance concrete, self-compacting concrete, self-leveling concrete, self-compacting concrete, fiber concrete, ready-mix concrete or colored concrete. According to this definition, prestressed concrete is also meant. The term "concrete" includes mortars. In this specific case, the concrete comprises a mixture of hydraulic binder, sand, water and possibly additives and possibly mineral additions. The term "concrete" according to the invention also includes a cement slurry or a mortar.

By the term "hydraulic binder" is meant according to the present invention a material which takes and hardens by hydration, for example a cement.

The product according to the invention is preferably a structural concrete, generally having a compressive strength measured at 28 days greater than or equal to 12 MPa, in particular between 12 MPa and 300 MPa. This concrete can be used in the supporting structure of a structure. A supporting structure is generally all the elements of a structure carrying more than their own weight. As an example of an element that can be a carrier, there may be mentioned poles, floors, walls, beams, lintels, piers, acroteria.

Preferably, the plasma-deposited chemical vapor deposition or plasma-deposited polymer composition exhibits high stability with respect to high temperatures under partial vacuum and high adhesion with the concrete.

The surface of the concrete is coated, in whole or in part, with a polymer composition deposited by plasma-assisted chemical vapor or gas deposition. This guy deposit is also called in the following text "plasma technology" or "plasma deposit" or also "PECVD". This plasma-assisted chemical vapor or gas deposition consists in creating a conductive gas (plasma) from monomers subjected to discharges generated by radiofrequency sources (preferably at 13.56 MHz) or by microwave sources ( preferentially at 2.45 GHz) or else by a voltage between two electrodes.

By the term "plasma" is meant a gas in which a large percentage of atoms or molecules is ionized. The generation of this state of matter is noticeably stable under a partial vacuum (from a few miliTorr to a few Torr), as performed in plasma technology reactors with inductive or capacitive coupling. Plasma contains notably free electrons and free radicals, capable of combining to form polymers.

A composition of unpolymerized reactive monomers and / or prepolymers is sent to the plasma technology reactor. Preferably, this composition is a composition of unpolymerized reactive monomers and prepolymers. This composition generally comprises one or more saturated or unsaturated groups. These plasma polymerizable groups include acrylates, alkyl, amides, amines, aniline, carbonates, ketones, epoxy, ethoxyl, glycidyl, imides, melamine, methacrylates, phthalates, silanes, silicones, stearates, styrene, vinyl.

The prepolymers or the final polymer deposit may further comprise one or more chlorine, bromine or fluorine atoms; but also one or more groups of the type: carboxyl, ethoxyl, hydroxyl, nitride.

One of the preferred compositions of unpolymerized reactive monomers and / or prepolymers comprises hexamethyldisiloxane (also known as HMDSO) to form polydimethylsiloxane of the general formula [O-Si (CH ₃ ) ₂ ] _{/ 1} (also called PDMS) after plasma polymerization.

The composition of unpolymerized reactive monomers and / or prepolymers may be applied in one or more layers. The total thickness of said composition deposited on the concrete is preferably from 0.05 to 100 microns, more preferably from 0.1 to 10 microns and even more preferably from 0.5 to 3 microns.

The polymerization of the reactive monomers and / or prepolymers takes place during deposition by plasma technology. The polymerization is carried out, for example, via condensation reactions, additions and / or crosslinking of the precursors of the polymer.

Polymer deposition by plasma technology can be performed at a speed of several micrometers thick per hour. The polymerization under plasma technology causes the formation of the polymer, for example in the form of a layer or a film.

Preferably, the polymer composition forms a polymer film. This polymer film is preferably continuous. According to a first variant, this polymer film is located on one side of the building material or the product which comprises this building material or the construction element which comprises this product. In particular, one side of the building material to be exposed to solar radiation is completely coated with the polymer.

According to another variant, it is possible to apply two or more polymer films, one on top of the other, on the substrate of construction material. In this case, the layers of polymer composition are superposed.

Preferably, the surface of the substrate of construction material on which the polymer composition is deposited has a roughness Ra before deposition of the polymer composition of from 0.5 μηη to 10 μηι, preferably from 0.5 to 7 μηι, even more preferably from 0.5 to 5 μηη, advantageously from 0.5 to 3 μηη.

The lower the surface roughness of the building material substrate prior to deposition of the polymer composition, the lower the thickness of the polymer composition may be.

On the other hand, the roughness of the surface of the substrate of construction material before deposition of the polymer composition is high and the thickness of the polymer composition must be raised so as to compensate for the surface irregularities of the substrate made of construction.

Preferably, the surface of the substrate of construction material on which the polymer composition is deposited has a roughness Ra after deposition of the polymer composition of from 0.1 μm to 5 μm, preferably from 0.2 to 3 μm, more preferably from 0.3 to 1 μηη, advantageously from 0.4 to 0.6 μηη.

By the term "roughness" is meant the irregularities of the order of one micrometer of a surface which are defined by comparison with a reference surface, and are classified in two categories: asperities or "peaks" or "protuberances" , and cavities or "hollows". The roughness of a given surface can be determined by measuring a number of parameters. In the remainder of the description, parameter Ra (measured by a confocal Micromesure full-field 3D confocal optical profilometer) is used, as defined by standards NF EN 05-015 and DIN EN ISO 4287 of October 1998, corresponding to the arithmetic mean of all the ordinates of the profile within a base length (in our examples, the latter was set at 12.5 mm).

Preferably, the surface of the polymer composition has a water porosity of less than 14%, preferably less than 12%, for example less than 10% (determined by the method described in the Proceedings Journées Techniques, AFPC-AFREM, December 1997, pages 121 to 124).

This promotes the subsequent deposition of a thin layer intended to form all or part of an electronic device.

Preferably, the thin layer that can be deposited on the polymer composition is based on inorganic / metallic compounds or organic compounds, or hybrid organic-mineral compounds (thin layers also called hybrid photovoltaic cells).

The inorganic and metallic compounds suitable for producing the thin layer intended to form all or part of an electronic device may be based on amorphous silicon, liquid silicon, cadmium telluride or copper-indium selenide (so-called CIS deposit). , copper-indium-gallium-selenide (CIGS deposit), copper-indium-gallium-diselenide-disulphide, copper-zinc-tin-sulfide-selenide (so-called CZTSSe deposit), copper-zinc-tin-sulfide (CZTS deposit), copper-zinc-tin-selenide (so-called CZTSe deposit), gallium arsenide (AsGa deposit), indium tin oxide (ITO deposit), copper, molybdenum , chalcopyrite or mixtures thereof.

The organic compounds suitable for producing the thin layer may be based on two compounds, one electron donor and the other electron acceptor. Among the electron donors, mention may be made of polyarylenes, poly (arylene-vinylene) s, poly (arylene-ethynylene) s or mixtures thereof. By way of example, mention may be made of poly-hexylthiophene (also known as P3HT)) or poly [2-methoxy-5- (3,7-dimethyloctyloxy) -1,4-phenylenevinylene] (also called MDMO-PPV).

Among the electron acceptors there may be mentioned compounds based on fullerene such as methyl [6,6] -phenyl-C61-butanoate (also known as PCBM).

The thin layer may also be composed of photosensitive pigments; we will then speak of dye cell or Graëtzel cell (also called DSSC or DSC).

Such cells comprise a transparent upper wall, a transparent photosensitive pigment disposed on the inner face of the upper wall, and an electrolyte bathing the assembly by conducting the conduction with the lower wall of the cell, which closes the circuit.

Among the photosensitive pigments constituting dyed photovoltaic cells or Graëtzel cells, mention may be made of titanium dioxide.

Preferably, the substrate of construction material is ultra-high performance concrete (BUHP). This high-performance concrete preferably has a water-cement ratio (W / C) of at most 0.45, preferably at most 0.32, more preferably from 0.20 to 0.27. The concrete may be a concrete containing silica fume.

Preferably, the concrete comprises, in parts by mass:

100 of Portland cement; 50 to 200 of sand having a single particle size with a D10 at a D90 of 0.063 to 5 mm, or a mixture of sands, the finest sand having a D10 at a D90 of 0.063 to 1 mm and the sand the most coarse having a D10 to a D90 of 1 to 5 mm, for example between 1 and 4 mm;

0 to 70 of a pozzolanic or non-pozzolanic material of particles, or a mixture thereof, having an average particle size of less than 15 μηη;

0.1 to 10 of a water reducing superplasticizer; and

10 to 32 of water, especially 20 to 32 of water.

The ultra-high performance concrete mentioned above generally has a compressive strength measured at 28 days greater than or equal to 50 MPa, in particular ranging from 50 MPa to 300 MPa, in particular greater than or equal to 80 MPa, especially from 80 to 80 MPa. 250 MPa. The concrete is preferably ultra-high performance concrete (BUHP), for example containing fibers. An ultra high performance concrete is a particular type of high performance concrete and generally has a compressive strength at 28 days greater than or equal to 100 MPa and in particular greater than or equal to 120 MPa. The polymer film and the thin film are preferably applied to elements made with ultra-high performance concretes described in patents US6478867 and US6723162 or patent applications EP1958926 and EP2072481.

D90, also D _v 90, is the 90 ^th percentile of the grain size volume distribution, ie 90% of the grains are smaller than D90 and 10% are larger than D90. Similarly, D10, also denoted D _v 10 corresponds to the io ^th percentile of the distribution by volume of grain size, that is to say 10% of the grains have a size smaller than the D10 and 90% have larger than the D10.

The sand is usually silica sand or limestone sand, calcined bauxite or metallurgical waste particles, the sand may also comprise a crushed mineral hard material, for example, a crushed vitrified slag.

BUHPs generally have greater shrinkage at setting due to their higher cement content. The total shrinkage can be reduced by the inclusion, generally from 2 to 8, preferably from 3 to 5, for example about 4 parts, of quicklime, lime or calcium oxide in the mixture before the addition of water.

Suitable pozzolanic materials include fumed silica, also known as micro-silica, which is a by-product of the production of silicon or ferrosilicon alloys. It is known as a pozzolanic reactive material.

Its main constituent is amorphous silicon dioxide. The individual particles generally have a diameter of about 5 to 10 nm. The particles Individuals agglomerate to form agglomerates of 0.1 to 1 μηη, and then can aggregate together into aggregates of 20 to 30 μηη. The silica fumes generally have a BET surface area of 10 to 30 m ² / g.

Other pozzolanic materials include materials rich in aluminosilicate such as metakaolin and natural pozzolans with volcanic, sedimentary, or diagenic origins.

Suitable non-pozzolanic materials also include materials containing calcium carbonate (eg ground or precipitated calcium carbonate), preferably ground calcium carbonate. Ground calcium carbonate may, for example, be the Durcal ^® 1 (OMYA, France).

The non-pozzolanic materials preferably have an average particle size of less than 5 μηη, for example from 1 to 4 μηη. Non-pozzolanic materials may be ground quartz, for example C800 which is a substantially non-pozzolanic silica filler supplied by Sifraco, France.

The preferred BET surface (determined by known methods) of calcium carbonate or crushed quartz is from 2 to 10 m ² / g, generally less than 8 m ² / g, for example from 4 to 7 m ² / g, preferably less than 6 m ² / g.

Precipitated calcium carbonate is also suitable as a non-pozzolanic material. Individual particles generally have a size (primary) of the order of 20 nm. The individual particles agglomerate into aggregates having a (secondary) size of about 0.1 to 1 μηη. The aggregates themselves form clusters having a size (ternary) greater than 1 μηη.

A non-pozzolanic material or a mixture of non-pozzolanic materials may be used, for example ground calcium carbonate, ground quartz or precipitated calcium carbonate or a mixture thereof. A mixture of pozzolanic materials or a mixture of pozzolanic and non-pozzolanic materials can also be used.

The concrete may be used in combination with reinforcing elements, for example metal and / or organic fibers and / or glass fibers and / or other reinforcing elements described hereinafter.

The concrete may comprise metal fibers and / or organic fibers and / or glass fibers. The amount by volume of fibers is generally from 0.5 to 8% relative to the volume of the hardened concrete. The amount of metal fiber expressed in terms of volume of the final hardened concrete is generally less than 4%, for example 0.5 to 3.5%, preferably about 2%. The amount of organic fibers, expressed on the same basis, is generally 1 to 8%, preferably 2 to 5%. The metal fibers are generally selected from steel fibers, such as fibers high-strength steel, amorphous steel fibers or stainless steel fibers. The steel fibers may optionally be coated with a non-ferrous metal such as copper, zinc, nickel (or their alloys).

The individual length (I) of the metal fibers is generally at least 2 mm and is preferably 10 to 30 mm. The ratio l / d (d being the fiber diameter) is generally 10 to 300, preferably 30 to 300, preferably 30 to 100.

Fibers having a variable geometry may be used: they may be creped, waved or hooked at the ends. The roughness of the fibers may also be modified and / or fibers of variable cross section may be used. The fibers can be obtained by any suitable technique, including braiding or wiring multiple wires, to form a twisted assembly.

Organic fibers include polyvinyl alcohol (PVA) fibers, polyacrylonitrile (PAN) fibers, polyethylene (PE) fibers, high density polyethylene (HDPE) fibers, polypropylene (PP) fibers, homopolymers or copolymers, polyamide or polyimide fibers. Blends of these fibers can also be used. The organic reinforcing fibers used can be classified as follows: high modulus reactive fibers, low modulus nonreactive fibers and low modulus reactive fibers. The presence of organic fibers makes it possible to modify the behavior of concrete in heat or fire.

The fusion of organic fibers makes possible the development of ways in which steam or pressurized water can escape when the concrete is exposed to high temperatures.

The organic fibers may be present as individual filaments or as bundles of several filaments. The diameter of the single filament or the bundle of multiple filaments is preferably from 10 μπι to 800 μηη. The organic fibers may also be used in the form of woven structures or nonwoven structures or a hybrid bundle comprising different filaments.

The individual length of the organic fibers is preferably from 5 mm to 40 mm, preferably from 6 to 12 mm. The organic fibers are preferably PVA fibers.

The optimum amount of organic fibers used generally depends on the geometry of the fibers, their chemical nature and their intrinsic mechanical properties (eg elastic modulus, yield point, strength).

The ratio l / d, d being the diameter of the fiber and I the length, is generally

10 to 300, preferably 30 to 90. The glass fibers may be single filament (monofilament fiber) or multiple filament (multifilament fiber) each individual fiber then comprising a plurality of filaments.

The glass fibers may be formed by pouring molten glass into a die. A conventional aqueous sizing composition can then be applied to the glass fibers. Aqueous sizing compositions may include a lubricant, a coupling agent and a film former and optionally other additives. The treated fibers are generally heated to remove water and heat-treat the sizing composition on the surface of the fibers.

The volume percentage of glass fibers in the concrete is preferably greater than 1% by volume, for example from 2 to 5%, preferably from about 2 to 3%, a preferred value being about 2%.

The diameter of the individual filaments in the multifilament fibers is generally less than about 30 μηη. The number of individual filaments in each individual fiber is generally 50 to 200, preferably about 100. The composite diameter of the multifilament fibers is generally 0.1 to 0.5 mm, preferably about 0.3 mm. . They generally have an approximately circular shape in cross section.

The glass generally has a Young's modulus greater than or equal to 60 GPa, preferably 70 to 80 GPa, for example 72 to 75 GPa, preferably about 72 GPa.

The length of the glass fibers is generally greater than the particle size of the granulate (or sand). The length of the fibers is preferably at least three times larger than the particle size. A mixture of lengths can be used. The length of the glass fibers is generally 3 to 20 mm, for example 4 to 20 mm, preferably 4 to 12 mm, for example about 6 mm.

The tensile strength of the multifilament glass fibers is about 1700 MPa or more.

The saturation dose of the glass fibers (S _f ) in the composition is expressed by the formula:

S _f = V _f x L / D

where V _f is the actual volume of the fibers. In ductile compositions, S _f is generally from 0.5 to 5, preferably from 0.5 to 3. In order to obtain a good fluidity of the fresh concrete mixture S _f can generally be up to about 2. The volume Real can be calculated from the weight and density of glass fibers.

Binary hybrid fibers comprising glass fibers and (a) metal fibers or (b) organic fibers and ternary hybrid fibers comprising glass fibers, metal fibers and organic fibers may also be used. A mixture of glass fibers, organic fibers and / or metal fibers can also be used: a "hybrid" composite is thus obtained whose mechanical behavior can be adapted according to the desired performance. The compositions preferably comprise polyvinyl alcohol (PVA) fibers. PVA fibers generally have a length of 6 to 12 mm. They generally have a diameter of 0.1 to 0.3 mm.

The use of fiber mixtures with different properties and lengths makes it possible to modify the properties of the concrete that contains them.

Suitable cements for concrete are the Portland Silica-Free Cements described in "Lea's Chemistry of Concrete and Concrete". Portland cements include slag, pozzolana, fly ash, shale, limestone and composite cements. A preferred cement is CEM I. The concrete cement is for example a white cement.

The water / cement mass ratio of concrete may vary if cement substitutes are used, more particularly pozzolanic materials. The water / binder ratio is defined as the mass ratio between the quantity of water E and the sum of the quantities of cement and of all pozzolanic materials: it is generally from 15 to 30%, preferably from 20% to 25%, percentage in mass. The water / binder ratio may be adjusted using, for example, water reducing agents and / or superplasticizers.

In the book "Concrete Admixtures Handbook, Properties Science and Technology", V.S. Ramachandran, Noyes Publications, 1984:

A water reducer is defined as an additive that reduces the amount of mixing water for a concrete for a given workability typically of 10 to 15%. Water reducers include, for example, lignosulphates, hydroxycarboxylic acids, carbohydrates, and other specialized organic compounds, for example glycerol, polyvinyl alcohol, sodium aluminum-methyl-siliconate, sulfanilic acid and casein.

Superplasticizers belong to a new class of water reducers that are chemically different from normal water reducers and capable of reducing the amount of mixing water by about 30%. Superplasticizers have been broadly classified into four groups: sulphonated naphthalene formaldehyde condensate (or SNF), (generally a sodium salt); sulphonated formaldehyde melamine condensate (or SMF, acronym for Sulphonated Melamine Formaldehyde Condensate); modified lignosulphonates (or MLS, acronym for Modified Lignosulfonates); and others. Next generation superplasticizers include polycarboxylic compounds such as polyacrylates. The superplasticizer is preferably a new generation of superplasticizer, for example a copolymer containing polyethylene glycol as a graft and carboxylic functions in the main chain such as a polycarboxylic ether. Sodium polysulphonate polycarboxylate and sodium polyacrylates can also be used. The amount of superplasticizer generally required depends on the reactivity of the cement. The lower the reactivity of the cement, the lower the required amount of superplasticizer. In order to reduce the total amount of alkaline, the superplasticizer can be used as a calcium salt rather than a sodium salt.

Other additives may be added to the concrete, for example an antifoaming agent (eg, polydimethylsiloxane). It is also silicones in the form of a solution, a solid or preferably in the form of a resin, an oil or an emulsion, preferably in water.

The amount of such an agent in the composition is generally at most 5 parts by weight relative to the weight of the cement.

The concretes of the product according to the invention may also comprise hydrophobic agents for increasing the repulsion of water and reducing the absorption of water and penetration into solid structures comprising concretes. Such agents include silanes, siloxanes, silicones and siliconates; commercially available products include liquid and solid products which can be diluted in a solvent, for example into granules.

Concrete can be prepared by known methods, including mixing of solid components and water, shaping (molding, casting, injection, pumping, extrusion, calendering) and then curing.

In order to prepare the concrete of the product according to the invention, the constituents and the reinforcing fibers are mixed with water. The following order of mixing may, for example, be adopted: mixing of the powder constituents of the matrix; introduction of water and a fraction, for example half, of adjuvants; mixed ; introduction of the remaining fraction of adjuvants; mixed ; introduction of reinforcing fibers and other constituents; mixed.

Reinforcing means used in combination with the concrete of the product according to the invention also comprise prestressing reinforcement means, for example, by adhering yarns or by adherent strands, or by post-tensioning, by non-adherent strands or by cables or by sheaths or bars, the cable comprising a set of wires or comprising strands.

In the mixture of the concrete components of the product according to the invention, the materials in the form of particles other than cement may be introduced as pre-mixtures or dry premix of diluted or concentrated aqueous powders or suspensions. The specific surfaces of the materials are measured by the BET method using a Beckman Coulter SA 3100 apparatus with nitrogen as the adsorbed gas.

Preferably the concrete of the product according to the invention is a self-compacting concrete, that is to say that it is put in place under the sole effect of gravity without it being necessary to vibrate. In particular, the concrete of the product according to the invention is a self-consolidating concrete as described in documents EP981506 or EP981505.

PROCESS

The subject of the invention is also a process for coating a substrate made of construction material, in particular concrete, comprising a step of depositing a polymer composition by plasma or vapor-assisted chemical vapor deposition on all or part of it the surface of the substrate of construction material, and a step of applying a thin layer intended to form all or part of an electronic device, in particular operating on the basis of the photovoltaic effect, and arranged on all or part of of the polymer composition.

According to one implementation of the method, the step of applying the thin layer is carried out by plasma-assisted chemical or vapor deposition.

This arrangement makes it possible to use the same deposit method for depositing the polymer composition and for depositing the photovoltaic thin film.

In addition, this makes it possible to optimize the efficiency of the coating process, in particular by keeping the concrete under vacuum between the two sequential deposition steps, which has the effect of preserving the homogeneity of recovery by the different layers and of improving the adhesion between the different layers.

Before the step of depositing the polymer composition, the method according to the invention may optionally comprise a pretreatment step of the concrete surface.

Preferably this pretreatment step takes place when the surface of the concrete is bare or prior to deposition of the polymer composition. This pretreatment step is also referred to as cleaning or surface activation. This pretreatment step preferably takes place by plasma technology, preferably using an argon + oxygen gas mixture or a gas mixture comprising ammonia.

The method according to the invention may optionally comprise a step of polishing the surface of the concrete before the application of the polymer composition comprising monomers and / or reactive prepolymers.

Preferably, the method according to the invention further comprises a pretreatment step of the concrete surface by plasma technology before deposition of the polymer composition. This step can take place using either pure oxygen, an argon + oxygen mixture. This step precedes that of the plasma deposition of polymers.

After the deposition step of the polymer composition and before the deposition step of the photovoltaic thin film, the method according to the invention may optionally comprise a step of post-treatment of the polymer surface by oxidation or nitrification under plasma . This post-treatment step is also referred to as activation of the polymer surface.

This post-treatment step may for example use an argon + oxygen gas mixture or a gas mixture comprising ammonia to modify the extreme surface chemical composition of the deposited plasma polymer composition.

This post-treatment step by plasma technology makes it possible to greatly improve the adhesion of the photovoltaic thin film to the polymer layer.

According to one variant, the method according to the invention may comprise a step mechanical treatment of the surface of the polymer composition deposited on the concrete, for example by roughing and then polishing. This treatment makes it possible to obtain a surface of average roughness of less than 3 μηη, preferably less than 1 μηη.

Advantageously, the deposition by plasma technology of the polymer composition allows a good homogeneous distribution of the polymer composition. In addition, the polymerization has the advantage of being rapid of the order of a few minutes (preferably less than 2 hours), which reduces the cycle and storage times associated with the application and drying of the polymer.

Advantageously, the deposition by plasma technology of the polymer composition makes it possible to obtain a sealing of the surface of the substrate of construction material with respect to the flow of water and of calcium salts, which for concrete limits the phenomena surface scumming and efflorescence that could compromise the adhesion of the thin layer to the polymer composition.

Advantageously, the deposition by plasma technology is implemented on the hardened concrete as quickly as possible after the end of the demolding, preferably 7 days after demolding, even more preferably 28 days after demolding.

The application of a thin layer to the polymer composition previously deposited by plasma technology is by plasma-assisted chemical vapor deposition or plasma vapor deposition.

The method according to the invention is particularly suitable for treating a high-performance concrete having at least one of the above characteristics.

The invention also relates to an element for the field of construction comprising a product according to the invention and as defined above. By the term "element for the field of construction" is meant according to the present invention any element or part of an element of a construction such as for example a foundation, a base, a wall, a beam, a pillar, a bridge stack, a block, a block, a pole, a staircase, a panel (including a façade panel), a cornice, a tile or a roof terrace.

The product according to the invention could possibly be used in "thin elements", for example those having a ratio between length and thickness greater than about 10, generally having a thickness of 10 to 30 mm, for example, elements coating.

In the present description, including the claims, unless otherwise indicated, the percentages are indicated by weight.

The invention will be described in more detail by means of the following non-limiting examples in connection with FIGS. 1 and 2 which respectively illustrate the device for measuring the contact / wetting angle of a drop of water. on a concrete surface (uncoated or coated with a polymer composition) and the different layers of a product according to the invention.

EXAMPLES

The following examples show how the concrete surface of the product (1) according to the invention withstands the conditions for deposition of thin layers (4), while allowing to obtain suitable surface properties for photovoltaic applications.

Such a product (1) according to the invention is illustrated in FIG.

The following components, used to make two separate concrete formulations, are available from the following suppliers:

(1) White Portland cement: Lafarge- France Le Teil

(2) Gray Portland Cement: Lafarge- France Val d'Azergues

(3) DURCAL 1: OMYA limestone filler

(4) BETOCARB HP limestone filler Orgon: OMYA

(5) Silica fumes MST: SEPR (European Society of Refractory Products) (6) Sand BE01: Sibelco France (Career of SIFRACO BEDOIN)

(7) Sand 0/4 mm: Lafarge France (St Bonnet Little Craz)

(8) Gravel 5/10 mm: Lafarge France (St Bonnet Little Craz)

(9) Ductal Adjuvant F2: Chryso

(10) Optima 203 Adjuvant: Chryso

(1 1) Vegetable oil Dem EC02: Chryso The Portland cements used are of the CEM I 52.5 type according to the EN 197-1 standard of February 2001. The silica fume has a median particle size of about 1 micron.

Formulation (F1) of Ultra High Performance Concrete:

The formulation (F1) of ultra-high performance concrete used to carry out the tests is described in Table (1) below:

Table (1): formulation (F1) of concrete

The water / cement ratio is 0.26. It is a concrete with a compressive strength at 28 days greater than 100 MPa.

The ultra high performance concrete according to the formulation (F1) was produced using a RAYNERI type mixer. The entire operation was performed at 20 ° C. The method of preparation includes the following steps:

• At T = 0 seconds: put the cement, calcareous filler, silica fumes and sand in the mixing bowl and knead for 7 minutes (15 rpm);

· At T = 7 minutes: add water and half of the adjuvant mass and knead for 1 minute (15 rpm);

• At T = 8 minutes: Add the remaining adjuvant and knead for 1 minute (15 rpm);

• At T = 9 minutes: mix for 8 minutes (50 rpm);

· At T = 17 minutes: knead for 1 minute (15 rpm).

• At T = 18 minutes: pour the concrete flat in the mold or molds provided for this purpose.

Plates (dimensions 180x20x10 mm) were produced by molding the concrete according to the formulation (F1) in a polyvinyl chloride (PVC) mold without form release agent. Each plate was demolded 18 hours after contact between cement and water. Each demolded plate was stored for 14 days at 25 ° C and 60% humidity. Following this storage, the concrete slabs were cut into smaller plates 10x10x2 mm, and only the plates whose surface was arranged opposite the bottom of the mold were used.

After storage for 14 days, a surface treatment was performed on a few plates. A first polymer composition (3) was applied to one side of a first plate via a first plasma deposition treatment (T1). A second comparative polymer composition (3) was applied to one side of a second plate via a second treatment (T2) by compressed air spraying. No polymer compositions were disposed on a third plate.

The two types of polymer compositions (3) are more precisely described later in the text and their difference is explained by the compatibility to be used with the treatment (T1) or (T2) considered.

The average roughness after demoulding (Ra, measured with optical profilometer) of the concrete according to the formulation (F1) of concrete is 0.4 μηη. In the present description, parameter Ra, as defined by DIN EN ISO 4287 of October 1998, is used, corresponding to the arithmetic mean of all the ordinates of the profile within a base length. This parameter Ra is measured using an optical profilometer (confocal 3D full-field micromesure) and using a spot size of 2.0 μηη, a working distance of 4.5 mm and a measurement step of 350 μηη. Under these conditions, the vertical and lateral resolutions are 0.01 μηη and 0.1 μηη, respectively.

Formulation (F2) of self-compacting concrete

The formulation (F2) of self-compacting concrete used to carry out the tests is described in Table (2) below:

Table (2): concrete formulation (F2)

The water / cement ratio is 0.49. It is a concrete with a compressive strength at 28 days greater than 25 MPa. The self-consolidating concrete according to the formulation (F2) is produced by means of a SIPE type mixer. The whole operation is carried out at 20 ° C. The method of preparation includes the following steps:

• At T = 0 seconds: put the gravel and sands in the mixing bowl and knead for 20 seconds;

• At T = 20 seconds: add the cement and filler and knead for 15 seconds (140 rpm); and

• At T = 35 seconds: add water and admixture and mix for 180 seconds (140 rpm) (T0 for the metering / setting time measurement method).

Plates (dimensions 180x120x15 mm) were made by molding the concrete according to the formulation (F2) in a steel mold, previously coated by spraying a liquid form release agent (Chryso DEM EC02) at a rate of 15 g / m ² . Each plate was demolded 20 hours after the contact between the cement and the water. Each demolded plate was stored for 14 days at 25 ° C and 60% humidity. Following this storage, the concrete slabs were cut to extract smaller plates of 10x10x2 mm.

As before, only the plates whose surface was arranged opposite the bottom of the mold were used.

After storage for 14 days, a surface treatment was performed on a few plates. The deposition of the first polymer composition (3) by plasma technology, said treatment (T1) was applied to one side of a first plate. The comparison deposit of the second polymer composition (3) by spraying, said treatment (T2) was applied to one side of a second plate. No deposit was made on a third plate.

The average roughness after demolding (Ra, defined by the DIN EN ISO 4287 standard of October 1998 and measured with the optical profilometer) of the concrete according to the formulation (F2) is 1, 1 μηι.

Process for depositing a first polymer composition (3) by plasma technology, said treatment (T1):

In the example presented, the deposition process is carried out in two steps: a step of preparing the surface of the concrete, and a step of depositing the polymer composition (3).

These two steps are carried out in an inductively coupled plasma reactor generated by a radiofrequency source ("Dressler César RF power generator" coupled with a "Matchwork control unit" of Eni Power System) The concrete is fixed on a sample holder, next to a glass slide, masked with a metal plate having four parallel slots that measure profilometry the average thickness of the deposit. The sample holder is placed vertically (perpendicular to the flow of gas) in the chamber, in the middle of the turns allowing the creation of the plasma by radio frequencies.

The first preparation step consists of cleaning and activating the concrete surface to be covered in order to increase the wettability of the concrete surface. Once the chamber is placed under a primary vacuum, this first preparation step is performed using a plasma of 0 ₂ .

The second step consists of the plasma deposition of the polymer composition (3).

The polymer composition (3) is created from a precursor (monomers) composed of hexamethyldisiloxane (also known as HMDSO). A secondary vacuum is first created in the chamber using a turbo-molecular pump, then the chamber is left under static vacuum by closing the valve connecting the turbo-molecular pump and the primary pump to the chamber and then by unplugging them.

The leakage valve connecting the chamber to the liquid HMDSO is then progressively opened. As soon as the pressure exceeds the threshold of 1 x10 ^"3 mbar thanks to the HMDSO vapors, the primary pump is reconnected and the valve connecting the primary pump to the chamber is reopened.While continuing to slowly open the leakage valve, the pressure 'HMDSO stabilizes at the desired value, eg 2x10 ^"1 mbar. Then, the inlet valve 0 ₂ is open and the flow of O ₂ increases, typically in this example at a pressure of 5x10 ^-1 mbar, if we consider that we have a dilution at 60% of 0 ₂ .

Table (3) summarizes effective operating conditions (60% dilution 0 ₂ ) used during the deposition, the polymer (3) polymerizes at the surface of the concrete to form a very compact layer of polydimethylsiloxane. Flow rates are given as standard cubic centimeters per minute (also known as sccm).

Table (3)

Compound steps Flow Pressure Radio-Power Pressure Chemical duration o ₂ partial in the frequency of (minutes)

(sccm) HMDSO room used dumps

(mbar) (mbar) (MHz) (Watt)

N ° 1 Dioxygen 5 0 1 .35 10 ^"1 13.56 100 2

N ° 2 HDMSO / 8 8.0 10 ^"2 2.0 10 ^{" 2} 13.56 80 60 o ₂ The deposition rate with a power of 80W was 14 nm of polymer per minute.

This deposition process was carried out on two types of concrete slabs, one obtained according to the formulation (F1) and the other obtained according to the formulation (F2).

The X-ray Photoelectron Spectroscopy (XPS) analyzes on the coating show that a SiOx ceramic film is obtained whose Si / O ratio is on average 0.6, ie SiOi _{, 6} and not a polymer layer. The analyzes of the SiOx coating thickness carried out over one hour give an average roughness value of between 0.8 and 0.9 μηι.

Measurements by profilometry have also shown that the roughness of the coating of

SiOx was equivalent to that of the initial substrate (2) (concrete formulations (F1) or (F2)). The deposit of SiOx thus marries well the initial roughness of the concrete.

However, the limited elasticity and plasticity, as well as the non-hydrophobic properties of such a ceramic film do not allow to consider the use of such a film for the subsequent deposition of a thin layer. Indeed, in addition to a lower resistance of the SiOx layer with respect to the thermal expansion stresses (with respect to a polymer layer), the SiOx type deposit is not sufficiently tight and hydrophobic to effectively protect the thin layers forming an electronic device vis-à-vis the rise of ionic solutions (efflorescences) from the substrate (2) of construction material (for example concrete type).

Tests have also been carried out showing that the use of a pulsed plasma was possible and also made it possible to deposit SiOx on the concrete without affecting the roughness. Under the conditions of Table (3), three tests at 50, 100 and 200 Hz pulses with a plasma pulsed at 50% and 50% off made it possible to deposit a half-thinner thickness.

Finally, other tests have shown that, by varying the oxygen dilution, it is possible to deposit a polymer composition (3) of general formula SiOxCy at speeds equivalent to or greater than those of the deposits described in Table (3). . For example, following the conditions described in Table (4), which proposes a dilution at only 20% in O ₂ , a deposition rate of 13.5 nanometers per minute is obtained and the deposited layer is according to the XPS layer. of SiOi.58Co.25- This test made it possible to deposit 1 μηη of polymer composition (3) on the formulation concretes (F1) and (F2), so as to obtain a roughness after deposition of 0.43 μηη on average.

Furthermore, the elasticity and the plasticity of such a SiOxCy-type polymer film (3), as well as its highly hydrophobic properties, make it possible to envisage the subsequent deposition. a thin layer (4) forming an electronic device. Indeed, the SiOxCy type deposit will be sufficiently tight and hydrophobic to effectively protect the thin layer (4) vis-à-vis the rise of ionic solutions (efflorescences) from the substrate (2) of construction material (for example of type concrete).

Table (4)

Plates comprising a polymer composition (3) deposited according to the conditions described in Table (4) were then used to perform various thin layer deposition tests (4), described below.

Comparative process for deposition of a polymer composition (3) by compressed air spraying, said treatment (T2):

The process was carried out at 20 ° C. and comprises, after waiting for 14 days after demolding the concrete to be treated, depositing, on the face of the concrete element to be treated, a first layer of a polymer acrylic diluted in an aqueous solvent (corresponding to Solarcir Primer Protec ™ product marketed by Grace-Pieri).

The emulsion was pulverized in an amount of 40 g / m ² . This process then included a waiting time of 24 hours from the drying of the first layer, then the deposition of a second polyurethane-based layer (corresponding to the Solarcir Protec Mat ™ product marketed by Grace-Pieri). This second layer was sprayed in an amount of 80 g / m ² .

This deposition process from the treatment (T2) was carried out on two types of concrete slabs, one obtained according to the formulation (F1) and the other obtained according to the formulation (F2). The plates were then used to perform the various tests and measurements described below.

Comparative studies between treatment (T1) and treatment (T2):

Durability of the surface visual aspect:

After being coated, concrete slabs made according to the formulations (F1) and (F2) were stored at 200 ° C. for 2 hours under partial vacuum (pressure <0.1 atmosphere) to check the resistance to deformation of the surfaces in a constraining environment, close to that required for the deposition of thin layers (4). A visual inspection was then performed to examine the plate surfaces and detect possible defects. The results of the visual inspections are presented in the following table (5):

Table (5)

The concrete slabs covered with the treatment (T1) do not show any stains or bubbles while the concrete slabs covered with the treatment (T2) comparison have at least one of these defects.

Variation of roughness and resistance to deformation:

Measurements of average roughness (parameter Ra) of the treated face of the coated concrete plates (and uncoated plates) were carried out before and after storage at 200 ° C. for 2 hours under partial vacuum (pressure <0.1 atmosphere) to verify the resistance to deformation of the surfaces in a constraining environment, close to that required for the deposition of thin layers (4). The results of the roughness measurements are presented in the following tables (6) and (7) according to the type of concrete formulation:

Table (6) for concretes manufactured according to the formulation (F1)

Concrete plate with the

Profilometry measurement of the concrete slab with

treatment (T2) average roughness (Ra) treatment (T1)

comparison

Before storage for 2 hours 0.4 μηη 2,0 m

at 200 ° C and under partial vacuum (+/- 0.1) (+/- 0.5 m)

After storage for 2 hours 0.4 μηη

> 5 m at 200 ° C and under partial vacuum (+/- 0.1) Table (7) for concretes manufactured according to the formulation (F2)

The concretes, regardless of their formulation, covered by the treatment (T1) do not show a variation of average roughness (Ra) whereas the concretes covered by the treatment (T2) comparison show a greater surface deformation; the concrete covered by the treatment (T1) is thus more favorable to the deposition of thin layer (4).

Angle of anchorage or contact

By the term "contact angle" or "wetting angle" is meant the angle formed between a liquid / vapor interface and a solid surface.

FIG. 1 illustrates the principle of measuring a wetting angle between a solid surface 10 of a concrete sample 12 and a drop 14 of a liquid deposited on the surface 10. The reference 16 is the interface liquid / gas between the drop 14 and the ambient air. FIG. 1 is a section on a plane perpendicular to the surface 10. In the section plane, the wetting angle α corresponds to the angle, measured from inside the liquid drop 14, between the surface 10 and the tangent T at the interface 16 at the point of intersection between the solid 10 and the interface 16.

To measure the wetting angle, the sample 12 is placed in a room at a temperature of 20 ° C and a relative humidity of 50%. There is a drop of water 14 having a volume of 2.5 μί on the surface 10 of the sample 12. The angle measurement is performed by an optical method, for example using a shape analysis device (English Drop Shape Analysis), for example the device DSA 100 marketed by Kruss. The measurements are repeated five times and the value of the contact angle measured between the drop of water and the support is equal to the average of these five measurements.

The measurement of the wetting angle was carried out for each concrete formulation with the treatment (T1), or with the treatment (T2) or without surface treatment using the test device of FIG. 1. The results are presented in the following table (8): Table (8)

Concrete, whatever its formulation, covered by the treatment (T1) is impervious than the concrete covered by the treatment (T2) comparison, and also more impervious than the concrete not covered by a coating. The high impermeability of the plates coated by the treatment (T1) reflects a very low surface open porosity, which is very favorable to the deposition of thin layers (4).

To be able to withstand a homogeneous deposition of thin layers (4), especially during deposition phases taking place under partial vacuum (10 ^"4 Torr) and with a concrete temperature brought to about 200 ° C (or more), the concrete should advantageously be:

- the smoothest and no surface deformation (Tables 5, 6 and 7),

- have an open surface porosity and the lowest possible liquid permeability (Table 8).

On reading the results given in the tables above, the formulation concretes (F1) or (F2) coated with a polymer composition (3) from the treatment (T1) (plasma technology deposition) are those which have the best surface characteristics for receiving a thin-film deposit (4).

Process for depositing a thin layer (4):

After selecting an ultra-high performance concrete formulation plate (F1) whose surface has been coated with a polymer composition (3) from the treatment (T1), conductive thin film deposition tests ( 4) to make the rear contact of an electronic device have been made with different materials and according to different methods.

1) Sputtering Molybdenum Deposition Test (Deposit No. 1)

The deposition was carried out by cathodic sputtering on two substrates (2) of formulation concrete (F1) covered with a polymer composition (3) made from the treatment (T1), under a pressure of 2 mTorr and an argon flow of 20 sccm in the plasma state. The Argon plasma was created using radio frequencies (13.56 MHz) with a power of 300 W.

Once these parameters were stabilized, the molybdenum target was exposed to the argon ion flux, resulting in a deposition rate of 22.2 nm / min. The two substrates (2) were mounted on a rotating sample holder which rotates at about 5 rpm, and left 13'30 "under the molybdenum flow to obtain a layer 300 nm thick.

In terms of roughness, the Ra after deposition is less than 0.4 μηη; the new surface thus obtained is therefore able to support a future deposit of photovoltaic layers based on CZTS (copper zinc tin sulfide).

2) Deposition of gold by evaporation under vacuum (deposit n ° 2):

The substrate (2) of formulation concrete (F1) coated with a polymer composition (3) made from the treatment (T1) has previously been treated for five minutes by a plasma of O ₂ generated at about 0, 1 mbar by radio frequencies at 100 W, with a flow of 0 ₂ of 5 sccm.

After this treatment, the chamber was placed in secondary vacuum (10 to 2 mbar). The substrate (2) was then placed under the gold source when the sublimation started under the effect of heating caused by heating a tungsten filament.

A deposit of 150 nm thick by evaporation of thinner layers (4) of gold was made. In terms of roughness, the Ra after deposition is less than 0.4 μηη.

3) Quality of deposits:

By applying a voltage and measuring the current, it was possible to measure the resistance of these molybdenum and gold metal deposits, and thus to go back to their resistivity in a very approximate way, notably by using the Van der Pauw method. . A resistivity of the order of 1 0 10 ^"4-1, 0 ^10" Q.cm ⁵ could be measured. The new surface thus obtained is therefore able to support a future deposit of photovoltaic layers based on CZTS.

Claims

1. Product (1) comprising:

a substrate of construction material (2),

a polymer composition (3) disposed on all or part of the surface of the building material (2), the polymer composition (3) being deposited by plasma-assisted chemical vapor or gas deposition, and

- A thin layer (4) intended to form all or part of an electronic device, in particular operating on the basis of the photovoltaic effect, and disposed on all or part of the polymer composition (3).

Product (1) according to claim 1, wherein the thin layer (4) is deposited on all or part of the polymer composition (3) by plasma-assisted chemical vapor or chemical vapor deposition.

Product (1) according to one of claims 1 or 2, wherein the surface of the substrate (2) on which is deposited the polymer composition (3) has a roughness Ra before deposition of the polymer composition (3) included 0.5 μηη at 10 μηι, preferably from 0.5 to 7 μηι, more preferably from 0.5 to 5 μηι, advantageously from 0.5 to 3 μηι.

Product (1) according to one of claims 1 to 3, wherein the surface of the substrate (2) on which is deposited the polymer composition (3) has a roughness Ra after deposition of the polymer composition (3) included from 0.1 μηη to 5 μηι, preferably from 0,

2 to 3 μηι, still more preferably 0,

3 to 1 μηι, advantageously 0,

4 to 0.6 μηι.

5. Product (1) according to one of claims 1 to 4, wherein the polymer composition (3) forms a polymer film.

6. Product (1) according to one of claims 1 to 5, wherein the building material (2) is a concrete.

7. A process for coating a substrate of construction material (2), especially concrete, comprising a step of depositing a polymer composition (3) by plasma-assisted chemical vapor or gas-phase chemical deposition on all or part of the surface of the substrate of construction material (2) and a step of applying a thin layer (4) intended to form all or part of an electronic device, in particular operating on the basis of the photovoltaic effect, and disposed on all or part of the polymer composition (3).

8. The method of claim 7, wherein the step of applying the thin layer (4) is performed by plasma-assisted chemical vapor deposition or vapor deposition.

The method of claim 8, wherein the plasma-assisted chemical vapor or chemical vapor deposition utilizes an argon-oxygen gas mixture or a gas mixture comprising ammonia.

The method according to one of claims 7 to 9, further comprising a plasma technology pretreatment step of the substrate surface of construction material (2) prior to deposition of the polymer composition (3).

1 1. The method according to one of claims 7 to 10, further comprising a plasma technology post-treatment step of the polymer composition (3), using an argon + oxygen gas mixture or a gas mixture comprising ammonia.

12. Element for the field of construction comprising a product (1) according to any one of claims 1 to 6.