Geometry-Dictated Wrinkle Patterns in Vapor-Deposited Thin Films

Surface patterns and wrinkles in thin films are of fundamental and technological interest for their utility in tuning morphological, mechanical, and surface properties. Here, we present a method to produce fluoropolymer films which spontaneously wrinkle when deposited onto soft substrates via the solvent-free initiated chemical vapor deposition (iCVD) process. The iCVD technique is a surface polymerization process that affords a wide monomer library and the ability to deposit polymers onto substrates of arbitrary shape. We demonstrate control over wrinkle pattern selection on silicone oil substrates as a function of surface topography, boundary shape, and deposition conditions. Here, we present relationships between substrate shape and wrinkle pattern selection, and we examine the underlying mechanism of wrinkling during film growth.