Surface modified expanded polytetrafluoroethylene devices and methods of producing the same

Abstract

Improved processes for surface treating expanded polytetrafluoroethylene (PTFE) is disclosed and improved surface-treated devices made from the processes. The processes employ a laser to surface-modify an expanded PTFE structure to create a macro-roughened surface that has the capability to remain microporous throughout. The unique process of the present invention creates a ridge and valley structure on the surfaces of devices that includes unique gnarled nodes along valley floors.

What is claimed is:  
     
         1 . A process for modifying a material surface, comprising the steps of: 
 a) providing an expanded PTFE material having a surface comprised of nodes and fibrils, the fibrils having lengths; and    b) exposing the expanded PTFE surface to an unfocused laser beam to form node clusters and gnarled nodes.    
     
     
         2 . The process of  claim 1  that further comprises using the laser beam to remove nodes and alter fibril lengths in order to form the node clusters and gnarled nodes.  
     
     
         3 . The process of  claim 1  that further comprises forming gnarled nodes having a protruding length and being substantially devoid of fibrils along the protruding length.  
     
     
         4 . The process of  claim 3  wherein the node clusters has a height and further comprises forming the gnarled nodes so that the protruding length of the gnarled node is greater than the height of the node clusters.  
     
     
         5 . The process of  claim 1  that further comprises forming a pattern in the material surface using the unfocused laser beam.  
     
     
         6 . The process of  claim 5  that further comprises forming a pattern of parallel grooves in the surface.  
     
     
         7 . The process of  claim 1  that further comprises the unfocused laser beam having a width applied to the surface of between about 1.5 and 3 mm.  
     
     
         8 . A process for forming an implantable material comprising providing a surface comprising expanded PTFE having a node and fibril microstructure; and 
 forming in said surface a textured pattern having multiple ridges and valley surfaces, so that the ridges comprise node clusters, said node clusters comprising multiple nodes interconnected by fibrils, and    the valley surfaces include gnarled nodes protruding therefrom, said gnarled nodes having a protruding length and being substantially devoid of fibrils along the protruding length.    
     
     
         9 . The process of  claim 8  that further comprises forming the textured pattern using a laser.  
     
     
         10 . The process of  claim 9  that further comprises using an unfocused laser to form the textured pattern.  
     
     
         11 . A process of treating a surface comprising providing a surface of expanded PTFE having nodes interconnected by fibrils and a thickness; 
 providing a laser having an unfocused beam;    applying the unfocused beam of the laser across the surface of the expanded PTFE with sufficient power and duration so as to form at least one valley in the surface but not enough power and duration to cut through the thickness of the expanded PTFE.    
     
     
         12 . The process of  claim 11  that further comprises forming a pattern in the surface using the unfocused laser beam.  
     
     
         13 . The process of  claim 12  that further comprises forming a pattern of parallel grooves in the surface.  
     
     
         14 . The process of  claim 11  that further comprises forming node clusters and gnarled nodes in the surface by applying the unfocused laser beam thereto.  
     
     
         15 . The process of  claim 14  that further comprises forming gnarled nodes having a protruding length and being substantially devoid of fibrils along the protruding length.  
     
     
         16 . The process of  claim 15  wherein the node clusters has a height and further comprises forming the gnarled nodes so that the protruding length of the gnarled node is greater than the height of the node clusters.  
     
     
         17 . The process of  claim 11  that further comprises providing a surface of expanded PTFE comprising an implantable medical device.  
     
     
         18 . The process of  claim 11  that further comprises the unfocused laser beam having a width applied to the surface of between about 1.5 and 3 mm.