Ultra-thin hydrophobic and oleophobic layer, method of manufacture and use in watchmaking as an epilame and in mechanical engineering as a barrier film

1. An ultra-thin hydrophobic and oleophobic layer, formed by self-assembly on a solid substrate surface, of compounds of the formula

A-B

in which

A represents a group of the formula

in which

Z represents C or N + ,

X represents C—H or C-L, L being an electron-attracting group selected from F, Cl, Br, I, CF 3 , NO 2 and N(CH 3 ) 3 + ,

Y represents H or CH 3 , or Y forms a 5- or 6-atom heterocycle with X,

T represents NH, CO, CONH or NH 2 + U − , U − being a soluble anion, and B represents a C 1 -C 20 linear aliphatic alkyl group partially or completely substituted with F.

2. An ultra-thin layer as claimed in claim 1 , wherein B is a linear aliphatic alkyl group perfluorinated in its terminal section, having the formula (CH 2 ) n —(CF 2 ) m CF 3

in which n is from 1 to 5 and m is from 4 to 11.

3. An ultra-thin layer as claimed in claim 2 , wherein n is from 1 to 3 and m from 5 to 9.

4. An ultra-thin layer as claimed in claim 1 , wherein A is selected from one of the following groups:

5. An ultra-thin layer as claimed in claim 1 , wherein it is obtained from N-(3,4-dihydroxyphenethyl)-4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoroundecanamide.

6. An ultra-thin layer as claimed in claim 1 , wherein the solid substrate is composed of a material selected from gold, silver, steel, aluminium, brass, bronze, copper-beryllium, titanium dioxide, ruby, sapphire, silicon, nickel, nickel phosphorus, iron, chromium, tantalum, yttrium, germanium, copper, platinum, metal oxides, ceramics, and polymers.

7. An ultra-thin layer as claimed in claim 6 , wherein the solid substrate comprises a ceramic selected from zirconia and niobia (niobium oxide).

8. An ultra-thin layer as claimed in claim 6 , wherein the solid substrate comprises a polymer selected from polyethylenes, polystyrenes, polyamides, polydimethylsiloxanes, polyvinyl chlorides, and epoxy resins.

9. An ultra-thin layer as claimed in claim 6 , wherein a surface of the substrate has been at least one of (i) covered or coated by an electroplating of gold, of gold-copper-cadmium and of gold, of nickel, of rhodium, of tin-nickel, (ii) treated by anodising, and (iii) modified by a surface treatment.

10. An ultra-thin layer as claimed in claim 9 , wherein the surface of the substrate has been modified by a surface treatment selected from oxidation, carburisation and nitriding.

11. An ultra-thin layer as claimed in claim 1 , wherein its advancing contact angle with water is at least 100° .

12. An ultra-thin layer as claimed in claim 1 , wherein its thickness measured by ellipsometry is from 0.5 to 10 nm.

13. A mechanical part, wherein it comprises an ultra-thin layer as claimed in claim 1 .

14. A mechanical part according to claim 13 , which is a watchmaking part.

15. A method of preparing an ultra-thin layer as claimed in claim 1 , wherein it comprises the immersion of the substrate in a solution of the compound of formula A-B in water or a mixture of water and protic solvent.

16. A method as claimed in claim 15 , wherein the protic solvent is 2-propanol.

17. Method of providing a barrier film to a substrate, comprising providing an ultra-thin layer as claimed in claim 1 .

18. Method of providing a barrier film as claimed in claim 17 , wherein the barrier film is an epilame provided to a watchmaking part.

19. An ultra-thin layer as claimed in claim 1 , wherein T represents NH 2 + U − , U − being a soluble anion selected from the group consisting of F − , Cl − , Br − , I, OH − , NO 3 − , HSO 4 − , SO 4 2− , CO 3 2− , HCO 3 − and SCN − .

20. An ultra-thin hydrophobic and oleophobic layer, formed by self-assembly on a solid substrate surface, of compounds of the formula

A-B

in which

A represents a group of the formula

in which

Z represents C or N + ,

X represents C—H or C-L, L being an electron-attracting group selected from F, Cl, Br, I, CF 3 , NO 2 and N(CH 3 ) 3 + ,

Y represents H or CH 3 , or Y forms a 5- or 6-atom heterocycle with X,

T represents NH, CO, CONH or NH 2 + U − , U − being a soluble anion, and B represents an unsubstituted C 1 -C 20 linear aliphatic alkyl group.

21. An ultra-thin layer as claimed in claim 20 , wherein A is selected from one of the following groups:

22. An ultra-thin layer as claimed in claim 20 , characterised by a compound of the following formula:

23. An ultra-thin layer as claimed in claim 20 , wherein the solid substrate is composed of a material selected from gold, silver, steel, aluminium, brass, bronze, copper-beryllium, titanium dioxide, ruby, sapphire, silicon, nickel, nickel phosphorus, iron, chromium, tantalum, yttrium, germanium, copper, platinum, metal oxides, ceramics, and polymers.

24. An ultra-thin layer as claimed in claim 23 , wherein the solid substrate comprises a ceramic selected from zirconia and niobia (niobium oxide).

25. An ultra-thin layer as claimed in claim 23 , wherein the solid substrate comprises a polymer selected from polyethylenes, polystyrenes, polyamides, polydimethylsiloxanes, polyvinyl chlorides, and epoxy resins.

26. An ultra-thin layer as claimed in claim 23 , wherein a surface of the substrate has been at least one of (i) covered or coated by an electroplating of gold, of gold-copper-cadmium and of gold, of nickel, of rhodium, of tin-nickel, (ii) treated by anodising, and (iii) modified by a surface treatment.

27. An ultra-thin layer as claimed in claim 26 , wherein the surface of the substrate has been modified by a surface treatment selected from oxidation, carburisation and nitriding.

28. An ultra-thin layer as claimed in claim 20 , wherein its advancing contact angle with water is at least 100° .

29. An ultra-thin layer as claimed in claim 20 , wherein its thickness measured by ellipsometry is from 0.5 to 10 nm.

30. A watchmaking part, wherein it comprises an ultra-thin layer as claimed in claim 20 .

31. A method of preparing an ultra-thin layer as claimed in claim 20 , wherein it comprises the immersion of the substrate in a solution of the compound of formula A-B in water or a mixture of water and protic solvent.

32. A method as claimed in claim 31 , wherein the protic solvent is 2-propanol.

33. A method of preparing an ultra-thin layer as claimed in claim 20 , wherein it comprises the immersion of the substrate in a solution of the compound of formula A-B in a mixture of aprotic solvent and protic solvent.

34. Method of providing an epilame to a watchmaking substrate, comprising providing an ultra-thin layer as claimed in claim 20 .

35. An ultra-thin layer as claimed in claim 20 , wherein T represents NH 2 +U 31 , U − being a soluble anion selected from the group consisting of F − , Cl 31 , Br − , I, OH − , NO 3 − , HSO 4 31 , SO 4 2− , CO 3 2− , HCO 3 31 and SCN 31 .