Temperature-dependent dynamic moduli of Parylene-C columnar microfibrous thin films

Columnar microfibrous thin films (mu FTFs) of the polymer Parylene C with different microfiber inclination angles were fabricated using a physicochemical vapor deposition process whereby a collimated flux of hot monomers is obliquely directed towards a planar substrate. Each mu FTF was then subjected to cyclic elastic loading in one of two orthogonal directions lying wholly in the substrate plane: either (i) normal or (ii) parallel to the morphologically significant plane of the HE Dynamic storage and loss moduli were determined in the 1-80 Hz frequency range for temperatures between -40 degrees C and 125 degrees C. For all columnar mu FTFs, the storage and loss moduli for normal loading did not exceed their counterparts for parallel loading. All columnar mu FTFs were found to be softer than a bulk film of Parylene C. In both bulk and columnar forms, Parylene C was found to be rheologically not simple. (C) 2016 Elsevier Ltd. All rights reserved.