Coated materials

Abstract

A thin fluoropolymer film is bonded to a substrate for medical, filtration or packaging purposes by using a pulsed or combination of gas and electrical pulsed cold plasma polymerization procedures.

1 . A method of applying a fluoropolymer film to a porous or microporous or other body, comprising exposing the body to cold plasma polymerisation using a pulsed gas regime to form either (i) an adherent layer of unsaturated carboxylic (e.g. acrylic) acid polymer on the surface and then derivatising the polymer to attach a perfluoroalkyl group terminating in —CF 3  trifluoromethyl, or (ii) a polymer of a perfluorocarbon monomer.  
     
     
         2 . A method of applying a fluoropolymer film according to  claim 1  wherein a combination of electrical and gas pulsing is used.  
     
     
         3 . A method of applying a fluoropolymer film according to  claim 1  or  2  wherein the cold plasma polymerisation uses a perfluorocarbon monomer or an unsaturated carboxylic acid.  
     
     
         4 . A method of applying a fluoropolymer film according to  claim 1 ,  2  or  3  where both the “gas on” and “gas off” times are from 0.1 microsecond to 10 seconds.  
     
     
         5 . A method according to any preceding claim, wherein perfluorocarbon monomer is not used and wherein the pulsed gas used is oxygen.  
     
     
         6 . A method according to  claim 1 ,  2 ,  3 , or  4  wherein the pulsed gas used is a noble or inert gas or is hydrogen, nitrogen or carbon dioxide.  
     
     
         7 . A method according to  claim 2 ,  3 , or  4  wherein acrylic acid polymer precursor or perfluorocarbon monomer is pulsed directly without a process gas.  
     
     
         8 . A method according to any preceding claim wherein the body is not microporous.  
     
     
         9 . A method according to any preceding claim, wherein perfluorocarbon monomer is not used and wherein the plasma power applied is in the range 1 Watt to 100 Watt.  
     
     
         10 . A method according to  claim 9 , wherein the plasma power applied is 1.5 Watt to 7 Watt.  
     
     
         11 . A body having a hydrophobic surface obtained by a method according to any preceding claim.  
     
     
         12 . A body according to  claim 11 , whose substrate is carbonaceous, ceramic, metallic or a combination of these.