Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7901591 | Journal of Non-Crystalline Solids | 2015 | 6 Pages |
Abstract
The glass transition temperature (Tg) of poly(α-methyl styrene) (PαMS) films supported by silica is studied as a function of film thicknesses from ~ 17 to ~ 168 nm at three molecular weights of 1.3, 20 and 420 kg/mol. For the 20 and 420 kg/mol films, the glass transition temperature decreases with decreasing film thickness, consistent with previous results. But for the 1.3 kg/mol films, it becomes independent of the film thickness. We tentatively suggest the Tg depression to be caused by free volume excess at the polymer-air interface and that its influence diminishes at low enough molecular weights because of a chain stiffness effect.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Kun Geng, Fei Chen, Ophelia K.C. Tsui,