Method for preparing an organic film at the surface of a solid support under non-electrochemical conditions, solid support thus obtained and preparation kit

Abstract

This invention relates to a method for preparing an organic film at the surface of a solid support, with a step of contacting the surface with a liquid solution including (i) at least one protic solvent, (ii) at least one adhesion primer, and (iii) at least one monomer different from the adhesion primer and radically polymerisable, under non-electrochemical conditions, and allowing the formation of radical entities based on the adhesion primer. This invention also relates to a non-electrically-conductive solid support on which an organic film is grafted, and a kit for preparing an essentially polymeric organic film at the surface of a solid support.

Claims

1. A method for preparing an organic film at a surface of a solid support, comprising a step of contacting said surface with a liquid solution including: at least one protic solvent, at least one adhesion primer, at least one radically polymerisable monomer, said monomer being different from the adhesion primer, under non-electrochemical conditions generating radical entities based on the adhesion primer, and wherein the adhesion primer generates said radical entities independent of the surface on which said radical entities are intended to be grafted, to form an organic film on the surface of the solid support, the organic film being covalently grafted on the surface of the solid support, said organic film being polymeric or copolymeric and having a monomer unit sequence in which a first unit is bonded to the solid support and is a derivative of the adhesion primer and other units are derived from said adhesion primer and from polymerizable monomers.

2. The preparation method of claim 1, wherein said protic solvent is chosen from the group consisting of water acidified or not, acetic acid, hydroxylated solvents, ethyleneglycol, and mixtures thereof.

3. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt chosen from the group consisting of aryl diazonium salts, aryl ammonium salts, aryl phosphonium salts and aryl sulfonium salts.

4. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt chosen from the group consisting of aryl diazonium salts, aryl ammonium salts, aryl phosphonium salts and aryl sulfonium salts and wherein said aryl group is chosen from aromatic or heteroaromatic carbon structures, consisting of one or more aromatic or heteroaromatic cycles each comprising 3 to 8 atoms, the heteroatom(s) being N, O, P or S.

5. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt with the following formula (I):
R—N.sub.2.sup.+,A.sup.−  (I) in which: A represents a monovalent anion and R represents an aryl group.

6. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt with the following formula (I):
R—N.sub.2.sup.+,A.sup.−  (I) in which: A represents a monovalent anion and R represents an aryl group chosen from aromatic or heteroaromatic carbon structures, consisting of one or more aromatic or heteroaromatic cycles each comprising 3 to 8 atoms, the heteroatom(s) being N, O, P or S.

7. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt with the following formula (I):
R—N.sub.2.sup.+,A.sup.−  (I) in which: A represents a monovalent anion chosen from inorganic anions, halogeno borates and organic anions and R represents an aryl group.

8. The preparation method of claim 1, wherein said adhesion primer is chosen from the group consisting of phenyldiazonium tetrafluoroborate, 4-nitrophenyldiazonium tetrafluoroborate, 4-bromophenyldiazonium tetrafluoroborate, 4-aminophenyldiazonium chloride, 2-methyl-4-chlorophenyldiazonium chloride, 4-benzoylbenzenediazonium tetrafluoroborate 4-cyanophenyldiazonium tetrafluoroborate, 4-carboxyphenyldiazonium tetrafluoroborate, 4-acetamidophenyldiazonium tetrafluoroborate, 4-phenylacetic acid diazonium tetrafluoroborate, 2-methyl 4-[(2-methylphenyl)diazenyl]benzenediazonium sulphate, 9,10-dioxo-9,10-dihydro-1-anthracenediazonium chloride, 4-nitronaphthalenediazonium tetrafluoroborate and naphthalenediazonium tetrafluoroborate.

9. The preparation method of claim 1, wherein said adhesion primer concentration in said liquid solution is between around 10-6 and 5 M.

10. The preparation method of claim 1, wherein said radically polymerisable monomer is a molecule comprising at least one ethylene-type bond.

11. The preparation method of claim 1, wherein said radically polymerisable monomer is a molecule with the following formula (II): ##STR00002## in which the R.sub.1 to R.sub.4 groups, identical or different, represent a non-metallic monovalent atom, a hydrogen atom, a —COOR.sub.5 group in which R.sub.5 represents a hydrogen atom or a C.sub.1-C.sub.12, alkyl group, a nitrile, a carbonyl, an amine or an amide.

12. The preparation method of claim 1, wherein said radically polymerisable monomer is chosen from the group consisting of vinyl acetate, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate and their derivatives; acrylamides, cyanoacrylates, di-acrylates and di-methacrylates, tri-acrylates and tri-methacrylates, tetra-acrylates and tetra methacrylates, styrene, parachloro-styrene, pentafluoro-styrene, N-vinyl pyrrolidone, 4-vinyl pyridine, 2-vinyl pyridine, vinyl halides, di-vinylbenzene (DVB), and vinyl cross-linking agents based on acrylate, methacrylate and derivatives thereof.

13. The preparation method of claim 1, wherein the amount of said radically polymerisable monomer represents between 18 and 40 times the solubility of said monomer at room temperature in the liquid solution.

14. The preparation method of claim 1, wherein said liquid solution also contains at least one surfactant.

15. The preparation method of claim 1, wherein said method includes a preliminary step during which said polymerisable monomer is dispersed or emulsified in the presence of at least one surfactant, or by ultrasound, before it is mixed with the at least one protic solvent and the at least one adhesion primer.

16. The preparation method of claim 1, wherein the non-electrochemical conditions allowing for the formation of radical entities are chosen from the group consisting of thermal, kinetic, chemical, photochemical or radiochemical conditions and a combination thereof, to which the adhesion primer is subjected.

17. The preparation method of claim 1, wherein the non-electrochemical conditions allowing for the formation of radical entities are chemical conditions.

18. The preparation method of claim 1, wherein said liquid solution also includes one or more chemical initiators.

19. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a) adding said at least one monomer to a solution containing said at least one adhesion primer different from said monomer in the presence of said at least one protic solvent, b) placing the solution obtained in step (a) under said non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer, c) placing the surface of the solid support in contact with the solution of step (b).

20. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a′) placing the surface of the solid support in contact with a solution containing said at least one adhesion primer in the presence of said at least one protic solvent, b′) placing the surface of the solid support in contact with the solution of step (a′) under non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer, c′) adding said at least one monomer to the solution obtained in step (b′).

21. The preparation method of claim 1, wherein said method includes an additional step, prior to the film preparation, of cleaning the surface on which the organic film is to be formed.

22. The preparation method of claim 1, wherein the surface of said solid support has at least one atom capable of being involved in a radical reaction.

23. The preparation method of claim 1, wherein said solid support and/or the surface of said solid support are made of a material chosen from the group consisting of metals, wood, paper, cotton, felt, silicon, carbon nanotubes and fluoro-polymers.

24. The preparation method of claim 1, wherein said solid support is either electrically conductive or non-electrically conductive.

25. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt chosen from the group consisting of aryl diazonium salts, aryl ammonium salts, aryl phosphonium salts and aryl sulfonium salts and wherein said aryl group is chosen from aromatic or heteroaromatic carbon structures, mono- or polysubstituted, consisting of one or more aromatic or heteroaromatic cycles comprising 3 to 8 atoms, the substituent(s) containing one or more heteroatoms or alkyl groups in in C.sub.1 to C.sub.6.

26. The preparation method of claim 1, wherein said adhesion primer is a cleavable aryl salt with the following formula (I):
R—N.sub.2.sup.+,A.sup.−  (I) in which: A represents a monovalent anion and R represents an aryl group chosen from aromatic or heteroaromatic carbon structures, mono- or polysubstituted, consisting of one or more aromatic or heteroaromatic cycles comprising 3 to 8 atoms, the substituent(s) containing one or more heteroatoms or alkyl groups in C.sub.1 to C.sub.6.

27. The preparation method of claim 1, wherein said radically polymerisable monomer is chosen from the group consisting of aminoethyl, propyl, butyl, pentyl and hexyl methacrylamides.

28. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a′) placing the surface of the solid support in contact with a solution containing said at least one adhesion primer in the presence of said at least one protic solvent, and at least one chemical initiator, b′) placing the surface of the solid support in contact with the solution of step (a′) under non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer and based on said chemical initiator, c′) adding said at least one monomer to the solution obtained in step (b′).

29. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a′) placing the surface of the solid support in contact with a solution containing said at least one adhesion primer in the presence of said at least one protic solvent, and at least one monomer, b′) placing the surface of the solid support in contact with the solution of step (a′) under non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer.

30. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a′) placing the surface of the solid support in contact with a solution containing said at least one adhesion primer in the presence of said at least one protic solvent, at least one chemical initiator and at least one monomer, b′) placing the surface of the solid support in contact with the solution of step (a′) under non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer and based on said chemical initiator.

31. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a′) placing the surface of the solid support in contact with a solution containing said at least one adhesion primer in the presence of said at least one protic solvent and at least one monomer, b′) placing the surface of the solid support in contact with the solution of step (a′) under non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer, c′) adding at least one monomer to the solution obtained in step (b′).

32. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a′) placing the surface of the solid support in contact with a solution containing said at least one adhesion primer in the presence of said at least one protic solvent, at least one chemical initiator and at least one monomer, b′) placing the surface of the solid support in contact with the solution of step (a′) under non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer and possibly based on said chemical initiator, c′) adding at least one monomer to the solution obtained in step (b′).

33. The preparation method of claim 1, wherein said method includes the following steps, consisting of: a) adding said at least one monomer to a solution containing said at least one adhesion primer different from said monomer in the presence of said at least one protic solvent and at least one chemical initiator, b) placing the solution obtained in step (a) under said non-electrochemical conditions allowing for the formation of radical entities based on said adhesion primer and based on said chemical initiator, c) placing the surface of the solid support in contact with the solution of step (b).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 provides a diagrammatic representation of a sequential film (FIG. 1a) and a statistical film (FIG. 1b) prepared according to this invention.

(2) FIG. 2 provides a diagrammatic representation of the grafting methods of the prior art (FIG. 2a) and of the method according to this invention (FIG. 2b).

(3) FIG. 3 shows the IR spectrum of a gold plate treated according to an alternative of the method of this invention, i.e. with a solution of which the diazonium salt has been prepared in situ.

(4) FIG. 4 shows, for a gold plate according to an alternative of the method of this invention, the IR spectrum of said gold plate treated at different exposure times (FIG. 4a) and the IR spectrum of said treated gold plate as a function of the amount of iron filings (FIG. 4b).

(5) FIG. 5 shows the XPS spectrometry analyses (X photoelectron spectroscopy) of a conductive carbon felt (FIG. 5a) and of the same carbon felt on which an organic film is grafted, which film is prepared according to the method of this invention, i.e. from a diazonium salt created in situ and acrylic acid, in the presence of iron filings (AAP for acrylic acid polymer) (FIG. 5b).

(6) FIG. 6 shows the IR spectrum of a gold plate treated according to the method of this invention for forming a sequential film.

(7) FIG. 7 shows the IR spectrum of a gold plate treated according to the method of this invention for forming a statistical film.

(8) FIG. 8 shows the IR spectrum of a gold plate treated according to the method of this invention for forming a film based on a monomer that is insoluble in the reaction solvent.

(9) FIG. 9 shows the IR spectrum of a glass plate treated according to the method of this invention.

(10) FIG. 10 shows a photograph of carbon nanotubes (FIG. 10a) and a photograph of carbon nanotubes after a treatment according to the invention (FIG. 10b).

(11) FIG. 11 shows the IR spectrum of a PTFE plate treated according to the method of this invention.

(12) FIG. 12 shows the IR spectra obtained for a gold plate (FIG. 12a) and a titanium plate (FIG. 12b) treated identically according to the method of this invention, i.e. based on 2-hydroxyethylmethacrylate and a diazonium salt prepared in situ, in the presence of iron filings.

(13) FIG. 13 shows the photograph of a water drop on a pristine glass plate (FIG. 13a) and the photograph of a water drop on the same glass plate coated with p-butylmethacrylate (p-BuMA) according to the method of the invention (FIG. 13b).

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

(14) The following examples were performed in a glass cell. Unless otherwise indicated, they were conducted under normal conditions of temperature and pressure (around 25° C. under around 1 atm) in ambient air. Unless otherwise indicated, the reagents used were obtained directly on the market without any additional purification. The glass plates used had a surface of 1 cm.sup.2.

(15) No precaution was taken with regard to the composition of the atmosphere, and the solutions were not degassed. When the reaction time is not specified, the exposure of the surface to be treated with the reagent solution lasted for 1 to 15 minutes.

EXAMPLE 1

Preparation of a Film on a Gold Plate Using a Diazonium Salt Prepared In Situ and 2-hydroxyethylmethacrylate (HEMA) in the Presence of Iron Filings

(16) 4 ml of a solution of NaNO.sub.2 at 0.1 M in water were added to 4 ml of a solution of p-phenylenediamine at 0.1 M in HCl (0.5 M), in order to form the aminophenyl mono diazonium salt. 1 ml of HEMA, then 200 mg of iron filings were added to this diazonium salt solution. A gold plate was then added to the reaction medium for 15 min. The plate was then rinsed in water with acetone, and subjected to ultrasound in DMF and then in water before being dried.

(17) The XPS spectrometry (X photoelectron spectroscopy) and IR analyses confirm the presence of the film expected, of which the thickness increases with the reaction time. FIG. 3 shows the IR spectrum of a plate after the treatment.

(18) Table 1 provided below combines a set of thickness values obtained for the same reagents when their concentrations, the exposure time or the amount of filings were varied.

(19) TABLE-US-00001 TABLE 1 HEMA Diazonium Thickness (mol .Math. l.sup.−1) (mol .Math. l.sup.−1) Time (min) Iron (mg) (nm) 0.9 0.05 1 200 10 0.9 0.05 3 200 50 0.9 0.05 5 200 90 0.9 0.05 10 200 140 0.9 0.05 15 200 200 0.45 0.025 1 200 <10 0.45 0.025 3 200 20 0.45 0.025 5 200 40 0.45 0.025 10 200 90 0.45 0.025 15 200 120 0.9 0.05 10 5 <10 0.9 0.05 10 50 30 0.9 0.05 10 100 70 0.9 0.05 10 150 100 0.9 0.05 10 200 150

(20) The increase in the exposure time, the primer and the monomer concentrations, and the amount of filings, enables the thickness of the film formed to be increased.

EXAMPLE 2

Test of the Film Thickness

(21) To show the influence of various parameters on the thickness of the organic film, the method was applied to a gold plate, placed in the presence of a solution containing an adhesion primer, 4-aminophenyldiazonium, and a monomer, HEMA, under non-electrochemical conditions allowing for the formation of a radical entity based on the adhesion primer. This choice was motivated in particular by the presence of characteristic absorption bands at 1726, 1454 and 1166 nm of the poly-HEMA.

(22) A solution of adhesion primer in water was prepared by adding 4 ml of a solution of NaNO.sub.2 at 0.1 M (4.10.sup.−4 moles) to 4 ml of a solution at 0.1 M (4.10.sup.−4 moles) of p-phenylenediamine in HCl (0.5 M), under agitation. 1 ml (8.24 mmoles) of HEMA and a gold plate were added to this solution.

(23) 2-1 Influence of the Reaction Time

(24) The solution was then placed under non-electrochemical conditions allowing for the formation of radicals on the adhesion primer by adding 200 mg of iron filings. The plate was then removed from the reaction medium and immediately rinsed with water then acetone and dimethylformamide (DMF) under ultrasound, and finally dried under an argon current.

(25) As shown by the IR spectrum in FIG. 4a, the time of exposure of the sample to the reaction medium has an influence on the thickness of the film obtained. Indeed, the increase in the intensity of the absorption bands of the HEMA at 1726, 1454 and 1166 nm indicates an increase in the thickness of the film over time.

(26) The thickness of the films was measured using a profilometer: it ranged from 12 nm to 200 nm for an exposure time ranging from 1 to 15 minutes.

(27) 2-2 Influence of Non-Electrochemical Conditions Allowing for the Formation of Radicals on the Adhesion Primer

(28) Given that the amount of radicals present in the solution has a notable influence on the reaction, the method was carried out with a variable amount of iron filings for a reaction time set at 10 min.

(29) As shown by the IR spectrum in FIG. 4b, the amount of iron filings present in the reaction medium has an influence on the thickness of the film obtained. A minimum amount of filings is necessary in order to generate enough radicals in the reaction medium and make it possible to obtain a grafted film of an IR-detectable thickness. Beyond a certain maximum amount of filings, the variations in thickness of the film obtained are negligible.

EXAMPLE 3

Preparation of a Film on a Gold Plate Using Commercial p-nitrophenyldiazonium and HEMA in the Presence of Iron Filings

(30) The experiment was conducted according to the protocol described in example 2, using commercial p-nitrophenyldiazonium (Aldrich®) solubilised at 0.05 M in an HCl solution (0.5 M). The gold plate was then placed in the reactor for around 15 min. The plate was then rinsed with water and acetone, and subjected to ultrasound in DMF and then in water before being dried.

(31) As above, the XPS spectrometry (X photoelectron spectroscopy) and IR analyses confirmed the presence of the film expected, of which the thickness increases with the reaction time.

EXAMPLE 4

Preparation of a Film on a Gold Plate Using a Diazonium Salt Created In Situ and HEMA in a Basic Medium

(32) The procedure is identical to that of example 2. 0.3 ml of a NaOH solution at 2.5×10.sup.−3 M were substituted for the iron filings in order to allow for a slight increase in the pH to above 4.

(33) The XPS and IR analyses confirm the presence of the film expected, of which the thickness increases with the reaction time.

EXAMPLE 5

Preparation of a Film on a Conductive Carbon Felt Using a Diazonium Salt Created In Situ and Acrylic Acid (AA) in the Presence of Iron Filings

(34) The example was performed according to the procedure described in example 2. The monomer used in this case was acrylic acid (1 ml) and the sample was constituted by carbon felt.

(35) The XPS analysis, as shown by the spectrum of FIG. 5, confirms the presence of the expected film.

EXAMPLE 6

Preparation of a Sequential Film on a Gold Plate Using a Diazonium Salt Prepared In Situ, HEMA and AA in the Presence of Iron Filings

(36) First, a plate was prepared and cleaned according to the procedure of example 2.

(37) A new solution of the same diazonium salt was then prepared and, to it, 1 ml of acrylic acid, then 200 mg of iron filings were added. The plate previously prepared according to example 2 was then placed in the reaction medium for a variable time, at the end of which it was cleaned and dried as described above.

(38) FIG. 6 shows the IR spectrum obtained for such a plate after 15 minutes of reaction. The characteristic bands of the AAP (acrylic acid polymer) at 1590 and 1253 nm appear on the spectrum of example 2.

EXAMPLE 7

Preparation of a Statistical Film on a Gold Plate Using a Diazonium Salt Prepared In Situ, HEMA and AA in the Presence of Iron Filings

(39) The procedure used is identical to that of example 2, except that 0.5 ml of acrylic acid and 0.5 ml of HEMA were added to the diazonium salt solution.

(40) The IR spectrum obtained is shown in FIG. 7: it confirms the presence of the expected statistical film constituted in particular by the two monomers.

EXAMPLE 8

Preparation of a Film on a Gold Plate Using a Diazonium Salt Prepared in situ and 4-vinyl-pyridine (4VP) in the Presence of Iron Filings

(41) 200 mg of iron filings, then a dispersion of 1 ml of 4 vinyl-pyridine in 10 ml of water, prepared by an ultrasound treatment, were added to a diazonium salt solution prepared according to example 2, containing a gold plate.

(42) The IR spectrum obtained for the plate is shown in FIG. 8. The characteristic bands at 1602, 1554 and 1419 nm validate the presence of the expected film.

EXAMPLE 9

Preparation of a Film on a Glass Plate Using a Diazonium Salt Prepared In Situ and HEMA in the Presence of Iron Filings

(43) The protocol is identical to that of example 2, except that a glass plate is used in this case.

(44) The IR spectrum shown in FIG. 9 confirms the presence of the expected film, the thickness of which increases with the reaction time.

EXAMPLE 10

Preparation of a Film on Carbon Nanotubes Using a Diazonium Salt Prepared In Situ and HEMA in the Presence of Iron Filings

(45) 200 mg of iron filings and 1 ml of HEMA were added to a diazonium salt solution prepared as indicated in example 2. Then, 100 mg of multiwall carbon nanotubes in the form of a carpet were added to this solution. The layer, after reaction, was cleaned according to the protocol described in example 2 before being dried.

(46) The photographs obtained by scanning electron microscopy (SEM), shown in FIG. 10, correspond to nanotubes before (FIG. 10a) and after (FIG. 10b) treatment.

EXAMPLE 11

Preparation of a Film on a PTFE (Teflon®) Surface Using a Diazonium Salt Prepared In Situ and HEMA in the Presence of Iron Filings

(47) 4 ml of a solution of NaNO.sub.2 at 0.1 M in water were added to 4 ml of a solution of p-phenylenediamine at 0.1 M in HCl (0.5 M) so as to form the diazonium salt. 1 ml of HEMA, then 200 mg of iron filings were added to this diazonium salt solution. A Teflon® part measuring 4 cm.sup.2 was then introduced to the reaction medium for 15 min, the plate was then rinsed in water and acetone and exposed to ultrasound in DMF, then water, before being dried.

(48) The spectrometry and IR analyses (FIG. 11) confirm the presence of the expected film, the thickness of which increases with the reaction time.

EXAMPLE 12

Application of the Method to Different Samples

(49) The method was successfully applied to a large number of samples of various types, and different monomers were used. The diazonium salt used in this example was prepared in situ using p-phenylenediamine.

(50) The results obtained for each type of sample according to the monomer are shown in table 2 below. For each of the samples tested, the presence of the organic film was verified using IR spectra.

(51) TABLE-US-00002 TABLE 2 Support Monomer Time (min) Film Gold HEMA 15 yes Gold Acrylic acid 15 yes Gold Acrylonitrile 15 yes Silicon wafer HEMA 20 yes Silicon wafer Acrylic acid 20 yes Silicon wafer Acrylonitrile 20 yes Aluminium HEMA 30 yes Aluminium Acrylic acid 30 yes Aluminium Acrylonitrile 30 yes Nanotubes (c) HEMA 15 yes Nanotubes (c) Acrylic acid 15 yes Felt HEMA 15 yes Felt Acrylic acid 15 yes Felt Acrylonitrile 15 yes Platinum HEMA 15 yes Platinum Acrylic acid 15 yes Platinum Acrylonitrile 15 yes Stainless HEMA 15 yes steel Stainless Acrylic acid 15 yes steel Stainless Acrylonitrile 15 yes steel Zinc HEMA 15 yes Zinc Acrylic acid 15 yes Zinc Acrylonitrile 15 yes Titanium HEMA 15 yes Titanium Acrylic acid 15 yes Titanium Acrylonitrile 15 yes Nickel HEMA 15 yes Nickel Acrylic acid 15 yes Nickel Acrylonitrile 15 yes Wood HEMA 45 yes Paper HEMA 45 yes Cotton HEMA 45 yes Teflon® HEMA 30 yes

EXAMPLE 13

Preparation of a Film on Surfaces of Different Types (Gold Plate and Titanium Plate) for the Same Solution

(52) 4 ml of a solution of NaNO.sub.2 at 0.1 M in water were added to a solution of p-phenylenediamine at 0.1 M in HCl (0.5 M). 1 ml of HEMA, then 200 mg of iron filings were added to this diazonium salt solution. A gold plate and simultaneously a titanium plate measuring 4 cm.sup.2 were then placed in the reaction medium for 15 min. The plates were then rinsed with water and acetone, and subjected to ultrasound in DMF, then water, before being dried.

(53) The spectrometry and IR analyses (FIG. 12) confirm the presence of the expected film for the two substrates.

EXAMPLE 14

Preparation of a Film on a Glass Plate Using a Diazonium Salt Prepared In Situ and Butylmethacrylate in the Presence of Iron Filings

(54) 200 mg of iron filings, then a dispersion of 1 ml of butylmethacrylate (BUMA) in 10 ml of water prepared by ultrasound were added to a diazonium salt solution prepared according to example 2 and containing a glass plate that has been pre-cleaned by a “piranha” solution treatment (i.e. a mixture of 60/40 by volume of concentrated sulphuric acid and water oxygenated at 110 volumes). After a reaction time of 10 minutes, the plate is then cleaned and dried according to the procedures described above.

(55) A spot test was then performed on the glass plate thus coated (FIG. 13b) and on a pristine glass plate used as a control (FIG. 13a). A change in the physical property of the glass plate thus coated, which becomes water-repellent, can be observed by the variation in the surface angle between the drop and the surface.