Fibrillar, nanotextured coating and method for its manufacture

Abstract

A fibrillar, nanotextured coating is deposited on a substrate by contacting the substrate with a reaction mixture comprising a reagent which is hydrolyzable to produced a cross-linked reaction product, and a first solvent which solvates the reagent and the reaction product. The reagent is hydrolyzed so as to provide a cross-linked reaction product which is bonded to the substrate. The substrate is then contacted with a second solvent which is a non-solvent for the reaction product so as to cause nanoscopic phase separation of the reaction product, resulting in the formation of a fibrillar nanotextured coating which is bonded to the substrate. The thus produced coating may be subjected to further chemical modification. The method may be utilized to produce superhydrophobic coatings. Also disclosed are coatings made by the method of the present invention.

1 . A substrate having a fibrillar coating thereupon:
 said coating comprising the hydrolysis product of a silane, said coating having a fibrillar structure comprised of a plurality of nanofibers having one end thereof bound to said substrate.   
     
     
         2 . The coating of  claim 1 , further characterized in that its contact angle with regard to water is at least 170 degrees. 
     
     
         3 . The coating of  claim 2 , wherein said contact angle is at least 175 degrees. 
     
     
         4 . The coating of  claim 1 , wherein at least 70% of said nanofibers have a diameter in the range of 20-70 nanometers. 
     
     
         5 . The coating of  claim 1 , wherein said nanofibers are configured as a network of cross-linked fibers. 
     
     
         6 . The coating of  claim 1 , wherein said silane is of the formula:
   R n SiX 4-n      
       wherein n is in the range of 0-3; R is independently H or alkyl; and X is independently halogen or OSO 2 —CF 3 . 
     
     
         7 . A superhydrophobic coating, said coating being characterized in that the advancing and receding angles of contact thereof, with regard to water, are at least 179 degrees.