Interface and surface effects on the glass-transition temperature in thin polymer films

• DOI: 10.1039/fd9949800219
• Publication Date: 2004-04-15T10:29:54Z
• Authors: Joseph L. Keddie; Richard A. L. Jones; Rachel A. Cory
• Keywords: Polystyrene; Silicon oxide; Ellipsometry; Poly(N-isopropylacrylamide)

We have measured the thickness dependence of glass-transition temperature (Tg) thin films poly(methyl methacrylate)(PMMA) by using spectroscopic ellipsometry to detect discontinuity in thermal expansivity occurring at Tg. studied on two surfaces: native oxide silicon, and evaporated gold. The Tg PMMA a gold surface decreases with decreasing film thickness, accordance previous results for polystyrene silicon. suggest that air liquid-like layer exists whose size diverges as is approached from below. For however, we find slight increase thickness. speculate hydrogen bonding interface restricts mobility leads an Tg, outweighing effect free surface.