A method of coating a surface with a polymer layer, which method comprises exposing said surface to a plasma comprising a monomeric unsaturated organic compound which comprises a chain of carbon atoms, which are optionally substituted by halogen; provided that where the compound is a perhalogenated alkene, it has a chain of at least 5 carbon atoms; so as to form an oil or water repellent coating on said substrate. Suitable compounds for use in the methods are compounds of formula (I) where R 1 , R 2 and R 3 are independently selected from hydrogen, alkyl, haloalkyl or aryl optionally substituted by halo; provided that at least one of R 1 , R 2 or R 3 is hydrogen, and R 4 is a group X—R 5 where R 5 is an alkyl or haloalkyl group and X is a bond; a group of formula —C(O)O(CH 2 ) n Y— where n is an integer of from 1 to 10 and Y is a bond or a sulphonamide group; or a group —(O) p R 6 (O) q (CH 2 ) t — where R 6 is aryl optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0 or an integer of from 1 to 10, provided that where q is 1, t is other than 0. The method is particularly useful in the production of oil- and/or water repellent fabrics.
1. A method of coating a surface with a polymer layer, which method comprises exposing said surface to a pulsed plasma comprising a compound of formula (I)
where R 1 , R 2 and R 3 are independently selected from hydrogen, alkyl, haloalkyl or aryl optionally substituted by halo, provided that at least one of R 1 , R 2 and R 3 is hydrogen, and
R 4 is a group X—R 5 , where R 5 is an alkyl or haloalkyl group, and X is:
a bond; or
a group of formula —C(O)O(CH 2 ) n Y— where n is an integer of from 1 to 10 and Y is a bond or a sulphonamide group; or
a group —(O) p R 6 (O) q (CH2) t — where R 6 is aryl optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0 or an integer of from 1 to 10, provided that where q is 1, t is other than 0;
so as to form an oil and/or water repellent coating on said surface.
2. A method according to claim 1 wherein R 5 is a haloalkyl group.
3. A method according to claim 2 wherein R 5 is a perhaloalkyl group.
4. A method according to claim 3 wherein R 5 is a perfluoroalkyl group of formula C m F 2m+1 where m is an integer of 1 or more.
5. A method according to claim 4 wherein m is from 1-20.
6. A method according to claim 5 wherein m is from 6-12.
7. A method according to claim 1 wherein R 1 , R 2 and R 3 are independently selected from hydrogen or a C 1-6 alkyl or halo-C 1-6 alkyl group, provided that at least one of R 1 , R 2 and R 3 is hydrogen.
8. A method according to claim 7 wherein R 1 , R 2 and R 3 are all hydrogen.
9. A method according to claim 1 wherein X is a group of formula —C(O)O(CH 2 ) n Y— and Y is a sulphonamide group of formula —N(R 6 )SO 2 — where R 6 is hydrogen or alkyl.
10. A method according to claim 3 wherein the compound of formula (I) comprises a compound of formula (II)
CH 2 ═CH—R 5 (II)
where R 5 is as defined in claim 1 .
11. A method according to claim 1 wherein the compound of formula (I) is an acrylate of formula (III)
CH 2 ═CR 7 C(O)O(CH 2 ) n R 5 (III)
where n and R 5 are defined in claim 1 and R 7 is hydrogen or C 1-6 alkyl.
12. A method according to claim 1 wherein the surface is a surface of a fabric, metal, glass, ceramics, paper or polymer substrate.
13. A method according to claim 12 wherein the substrate is a fabric.
14. A method according to claim 1 wherein the gas pressure of the compound of formula (I) is from 0.01 to 10 mbar.
15. A method according to claim 1 wherein a glow discharge is ignited by applying a high frequency voltage.
16. A method according to claim 15 wherein pulses are applied in a sequence which yields low average power.
17. A method according to claim 16 wherein the average power density is equivalent to less than 10 W in a volume of 470 cm 3 .
18. A method according to either of claim 16 wherein the average power density is equivalent to less than 1 W in a volume of 470 cm 3 .
19. A method according to claim 15 wherein the sequence comprises a duty cycle (the ratio of time for which the power is on to the time for which the power is off) of between 1:500 and 1:1000.
20. A hydrophobic and/or oleophobic substrate which comprises a coating of a polymer which has been applied by the method according to claim 1 .
21. A hydrophobic and/or oleophobic substrate according to claim 20 wherein the polymer is a haloalkyl polymer.
22. A substrate according to claim 20 which is a fabric.
23. An item of clothing which comprises a fabric according to claim 22 .
24. A method of coating a surface with a polymer layer, which method comprises exposing said surface to a plasma comprising a monomeric unsaturated organic compound which comprises an optionally substituted hydrocarbon group wherein any optional substituents are halogen; provided that where the compound is a straight chain perhalogenated alkene, it comprises at least 5 carbon atoms, wherein the plasma is pulsed so as to provide a low average power, further wherein the average power density is equivalent to less than 1 W in a volume of 470 cm 3 .
25. A hydrophobic and/or oleophobic substrate which comprises a coating of a polymer which has been applied by the method according to claim 24 .
26. A substrate having a coating thereon, said coating being deposited by pulsed plasma deposition and being derived from a compound of formula (I)
where R 1 , R 2 and R 3 are independently selected from hydrogen, alkyl, haloalkyl or aryl optionally substituted by halo, provided that at least one of R 1 , R 2 and R 3 is hydrogen, and
R 4 is a group X—R 5 , where R 5 is an alkyl or haloalkyl group, and X is:
a bond; or
a group of formula —C(O)O(CH 2 ) n Y— where n is an integer of from 1 to 10 and Y is a bond or a sulphonamide group; or
a group —(O) p R 6 (O) q (CH2) t — where R 6 is aryl optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0 or an integer of from 1 to 10, provided that where q is 1, t is other than 0, the compound of formula (I) having been treated such that the double bond reacts to form the coating but otherwise, the structure of the monomer is substantially retained,
and wherein the coating is such that were it present on a planar glass surface, it would have a surface energy of 5-6 mNm −1 .
27. A method of coating a surface with a polymer layer, which method comprises exposing said surface to a pulsed plasma comprising a compound of formula (I)
R 1 R 2 C═CR 3 R 4 (I)
where R 1 , R 2 and R 3 are independently selected from hydrogen, alkyl, haloalkyl or aryl optionally substituted by halo, provided that at least one of R 1 , R 2 and R 3 is hydrogen, and R 4 is a group X—R 5 , where R 5 is a perhaloalkyl group having from 6 to 20 carbon atoms and X is:
a bond; or a group of formula —C—(O)O(CH 2 ) n Y— where n is an integer of from 1 to 10 and Y is a bond or a sulphonamide group; or
a group —(O) p R 6 (O) q (CH 2 ) t — where R 6 is aryl optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0 or an integer of from 1 to 10, provided that where q is 1, t is other than 0;
wherein a glow discharge is ignited by applying a high frequency voltage and wherein pulses are applied in a sequence which yields an average power density equivalent to less than 50 W in a volume of 470 cm 3 so as to form an oil and water repellent coating on said surface.
28. A method according to claim 27, wherein R 5 is a perfluoroalkyl group of formula C m F 2m+1 where m is an integer from 6 to 12.
29. A method according to claim 27, wherein the coating is such that were it present on a planar glass surface, it would have a surface energy of 5-6 mJm −1 .
30. A method according to claim 27, wherein the average power density is equivalent to less than 1 W in a volume of 470 cm 3 .
31. A hydrophobic and oleophobic substrate which comprises a polymer coated surface obtained by the method of claim 27.
32. A method of coating a surface with an oil and water repellent polymer layer, which method comprises exposing said surface to a pulsed plasma comprising a compound of formula (II)
CH 2 ═CHR 5 (II)
where R 5 is a C 6-20 perhaloalkyl group of formula C m F 2m+1 where m is an integer from 6 to 20, in which a glow discharge is ignited by applying a high frequency voltage, and in which the high frequency voltage is applied as a pulsed field, in which pulses are applied in a sequence which yields an average power density equivalent to less than 50 W in a volume of 470 cm 3 so as to form an oil and water repellent coating on said surface.
33. A method according to claim 32, wherein the coating is such that were it present on a planar glass surface, it would have a surface energy of 5-6 mJm −1 .
34. A method according to claim 32, wherein the average power density is equivalent to less than 1 W in a volume of 470 cm 3 .
35. A method according to claim 32, in which the sequence is such that the power is on for 20 μs and off for from 10,000 μs to 20,000 μs.
36. A hydrophobic and oleophobic substrate which comprises a polymer coated surface obtained by the method of claim 32.
37. A substrate according to claim 36, which is a fabric.
38. A method according to claim 32, wherein R 5 is a perfluoroalkyl group of formula C m F 2m+1 where m is an integer from 6 to 12.
39. A method of coating a surface with an oil and water repellent polymer layer, which method comprises exposing said surface to a pulsed plasma comprising a compound of formula (III)
CH 2 ═CR 7 C(O)O(CH 2 ) n R 5 (III)
where R 7 is hydrogen or C 1-6 alkyl, n is an integer of from 1 to 10 and where R 5 is a perfluoroalkyl group having from 6 to 20 carbon atoms,
in which a glow discharge is ignited by applying a high frequency voltage, and in which the high frequency voltage is applied as a pulsed field, in which pulses are applied in a sequence which yields an average power density equivalent to less than 50 W in a volume of 470 cm 3 so as to form an oil and water repellent coating on said surface.
40. A method according to claim 39, wherein the coating is such that were it present on a planar glass surface, it would have a surface energy of 5-6 mJm −1 .
41. A method according to claim 39, wherein R 5 is a perfluoroalkyl group of formula C m F 2m+1 where m is an integer from 6 to 12.
42. A method according to claim 39, wherein the average power density is equivalent to less than 1 W in a volume of 470 cm 3 .
43. A method according to claim 39, in which the sequence is such that power is on for 20 μs and off for from 10,000 μs to 20,000 μs.
44. A hydrophobic and oleophobic substrate which comprises a polymer coated surface obtained by the method of claim 39.
45. A substrate according to claim 44, which is a fabric.