Fluoroalkylated Silicon-Containing Surfaces - Estimation of Solid Surface Energy
Abstract
The design of robust omniphobic surfaces, which are not wetted by low surface tension liquids such as octane (gamma1v = 21.6 mN/m) and methanol (gammalv = 22.7 mN/m), requires an appropriately chosen surface micro/nano-texture in addition to a low solid surface energy (gammasv). 1H,1H,2H,2H-Heptadecafluorodecyl polyhedral oligomeric silsesquioxane (fluorodecyl POSS) offers one of the lowest solid surface energy values ever reported (gamma=sv 10 mN/m) and has become the molecule of choice for coating textured surfaces. In this work, we synthesize and evaluate a series of related molecules that either retain the POSS cage and differ in fluoroalkyl chain length or that retain the fluorodecyl chains surrounding a linear or cyclic molecular structure. The solid surface energy (gammasv) of these molecules was estimated using contact angle measurements on flat spin-coated silicon wafer surfaces. Zisman analysis was performed using a homologous series of n-alkanes (15.5 <=gammalv < equal 27.5 mN/m), while Girifalco-Good analysis was performed using a set of polar and non-polar liquids with a wider range of liquid surface tension (15.5 <=gamma lv <= 72.1 mN/m). The hydrogen bond donating, hydrogen bond accepting, polar and nonpolar (dispersion) contributions to the solid surface energy of each compound were determined by probing the surfaces using a set of three liquid droplets of either acetone, chloroform and dodecane or diiodomethane, dimethyl sulfoxide and water.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 20, 2010
- Accession Number
- ADA533426
Entities
People
- Brian M. Moore
- Gareth McKinley
- Jesus O. Guardado
- Joseph M Mabry
- Robert E. Cohen
- Shreerang S. Chhatre
- Timothy S. Haddad
Organizations
- Air Force Research Laboratory