31 - Girifalco: Good analysis of fluoroalkylated silicon-containing surfaces
Mr. Shreerang S Chhatre, Mr. Jesus O Guardado, Dr. Brian M Moore PhD, Dr. Joseph M Mabry PhD, Prof. Gareth H McKinley PhD, Prof. Robert E Cohen PhD Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States; Space and Missile Propulsion Division, Air Force Research Laboratory, Edwards Air Force Base, Lancaster, CA, United States
Fluorodecyl POSS has one of the lowest solid surface energies ever reported (gsv ~ 10 mJ/m2). Each silsesquioxane cage (T8) is surrounded by eight 1H,1H,2H,2H-heptadecafluorodecyl groups. We compared the surface wettability of fluorodecyl POSS with other T8 cages of varying side group length, and also with other -SiOx- moieties such as rings (Q4) and straight chains (M2). The effect of molecular architecture on wettability was assessed through advancing and receding contact angle measurements on flat silicon wafers spin-coated with a thin layer of each molecule. Surface energies estimated by Zisman analysis compared favorably with the Girifalco - Good analysis for a broad range of polar and non-polar liquids. The surface energy increased with lower cage complexity (T8 < Q4 < M2) and with decreasing perfluorinated chain length. The remarkably low surface energy of fluorodecyl POSS is provisionally attributed to favorable packing of the side chains and restricted molecular reorganization at the surface in the presence of a contacting liquid.
Sunday, August 22, 2010 10:10 AM
Symposium in Honor of Kash Mittal (08:30 AM - 11:50 AM)
Location: The Westin Boston Waterfront