Hydrophilic surfaces for reducing friction forces

Abstract

A substrate (for example an implantable medical device) is provided with a lubricious surface by grafting onto the surface monomers containing acrylamide groups and then hydrolysing said groups under alkaline conditions, the grafting step being carried out in an aqueous environment.

1 . A method of providing a substrate with a lubricious surface, including the steps of grafting onto the substrate in an aqueous environment a monomer containing an acrylamide functional group and then hydrolysing said functional group in alkaline conditions in order further to increase the lubricious nature of said surface. 
     
     
         2 . A method as claimed in  claim 1  wherein the monomer is acrylamide or N-N dimethylacrylamide. 
     
     
         3 . A method as claimed in  claim 1  wherein prior to the grafting step the surface of the substrate is activated to increase adhesion of the polymer. 
     
     
         4 . A method as claimed in  claim 3  wherein the activation is carried out by means of a plasma treatment, corona discharge, ozone treatment or by chemical activation. 
     
     
         5 . A method as claimed in  claim 3  wherein the surface activation results in hydroxyl groups being formed at the surface of the substrate. 
     
     
         6 . A method as claimed in  claim 1  wherein the substrate is a medical device. 
     
     
         7 . A method as claimed in  claim 1  wherein the substrate is formed from a polyether block amide. 
     
     
         8 . A method as claimed  claim 1  which is carried out on only a part of the substrate. 
     
     
         9 . A method as claimed in  claim 8  wherein the part of the substrate which is not to be treated is masked with a non-reactive polymer which is removed at the end of the method. 
     
     
         10 . A method as claimed in  claim 1  additionally comprising the step of attaching a bioactive to the hydrolysed functional group. 
     
     
         11 . A substrate having a lubricious surface obtainable by means of a method as claimed in  claim 1 .