Film is a material with small thickness but large, indeterminate width and length. Films can be a mm or more in thickness down to nm. Thus the critical dimension describing a film is its thickness. When they are very thick, they are generally called sheets. Tapes are films with narrow widths but indeterminate lengths. (RDC 11/3/2008) 

Blown Film
Extrusion Casting
  
Heat Shrinkable Film
Laminating Film
Materials   
Membrane Separations   
Nafion Films

Phosphoric Acid Membranes for Fuel Cells  
Polyamide-Imide Film   
Polyethylene Film   
Polyester Film 

Polyether Membranes for Fuel Cells    
Protein Films   
PTFE Film 
PVDC Film    
Solution Casting Films