Besancon Brian M, Soles Christopher L, Green Peter F
Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712, USA.
Phys Rev Lett. 2006 Aug 4;97(5):057801. doi: 10.1103/PhysRevLett.97.057801. Epub 2006 Jul 31.
The average glass transition temperatures, Tg, of thin homopolymer films exhibit a thickness dependence, Tg(h), associated with a confinement effect and with polymer-segment-interface interactions. The Tg's of completely miscible thin film blends of tetramethyl bisphenol-A polycarbonate (TMPC) and deuterated polystyrene (dPS), supported by SiO(x)/Si, decrease with decreasing h for PS weight fractions phi >0.1. This dependence is similar to that of PS and opposite to that of TMPC thin films. Based on an assessment of Tg(h, phi), we suggest that the Tg(h, phi) of miscible blends should be rationalized, additionally, in terms of the notion of a self-concentration and associated heterogeneous component dynamics.
均聚物薄膜的平均玻璃化转变温度Tg呈现出厚度依赖性Tg(h)，这与受限效应以及聚合物链段-界面相互作用有关。由SiO(x)/Si支撑的四甲基双酚A聚碳酸酯（TMPC）和氘代聚苯乙烯（dPS）完全互溶的薄膜共混物，当聚苯乙烯重量分数φ>0.1时，其Tg随着h的减小而降低。这种依赖性与聚苯乙烯的相似，与TMPC薄膜的相反。基于对Tg(h, φ)的评估，我们认为，此外，互溶共混物的Tg(h, φ)应根据自浓度概念和相关的非均相组分动力学来进行合理说明。
