Dielectric and dilatometric studies of glass transitions in thin polymer films
Dielectric and dilatometric studies of glass transitions in thin polymer films
复制标题
聚合物薄膜中玻璃化转变的介电和膨胀研究
DOI：
10.1051/jp4:2000748
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Y. Miyamoto
中科院分区：
文献类型：
--
作者：
K. Fukao;Y. Miyamoto
对聚苯乙烯薄膜进行了介电弛豫和热膨胀谱，以测量α过程引起的磁化率损失分量峰值对应的温度T α和α弛豫时间r作为膜厚度d的函数。当玻璃化转变温度Tg随膜厚的减小而降低时，当d > dc时，T α和r几乎保持不变，而当d <dc时，T α和r在高温下急剧降低。这里，dc是临界厚度。在玻璃化转变温度附近，T α和r的厚度依赖性更为显著。讨论了聚苯乙烯薄膜的脆性指数与非指数性之间的关系。
Dielectric relaxation and thermal expansion spectroscopy were made for thin polystyrene films in order to measure the temperature T α corresponding to the peak in the loss component of susceptibility due to the α-process and the α-relaxation time r as functions of film thickness d. While the glass transition temperature Tg decreases with decreasing film thickness, T α and r were found to remain almost constant for d > d c and decrease drastically for d < d c for high temperatures. Here, d c is a critical thickness. Near the glass transition temperature, the thickness dependence of T α and r is more prominent. The relation between the fragility index and non-exponentiallity is discussed for thin films of polystyrene.