| Impact Of Segmental Mobility On The Thermal And Mechanical Properties Of Thin Polymer Films | ||
| Casey G. Campbell, Department of Electrical Engineering, Arizona State University, Tempe, AZ 85284 and Bryan D. Vogt, Department of Chemical Engineering, Arizona State University, Tempe, AZ 85284 The thermal properties, especially Tg, of polymer thin films have been studied extensively for polystyrene, as functions of different physical properties ranging from surface energy of the support to molecular weight. Generally, Tg decreases with respect to the bulk value below a critical film thickness of approximately 30 nm. However, the presence of residual solvent can suppress or even eliminate the thickness dependence on Tg.1 Minimizing required cooperative segmental motion has been suspected to be the root of this behavior,1 and some modified styrenic-repeat unit structures tend to support this claim.2 Here we extend these studies to a homologous series of poly(alkyl methacrylates), whose bulk Tg and local segmental dynamics are directly related to the alkyl chain length. The impact of these small changes in the repeat structure on Tg, coefficient of thermal expansion (CTE), and Young's modulus is examined as a function of the film thickness. References: 1. C.J. Ellison, R.L. Ruszkowski, N.J. Fredin, J.M. Torkelson. Physical Review Letters 2004, 92, 095702. 2. C.J. Ellison, M.K. Mundra, J.M. Torkelson. Macromolecules 2005, 38, 1767. Extended Abstract Status: Not Uploaded | ||