Kang Hua, Qian Xiaoqin, Guan Li, Zhang Meining, Li Qiang, Wu Aoli, Dong Mingdong
Department of Chemistry, Renmin University of China, Beijing, 100872, People's Republic of China.
Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Dk-8000, Aarhus C, Denmark.
Nanoscale Res Lett. 2018 Jan 9;13(1):5. doi: 10.1186/s11671-017-2426-9.
The relaxation behaviors of thin polymer films show a strong dependence on temperature and film thickness. Direct quantitative detection of the relaxation behaviors of thin polymer films at nanometer scale by traditional instruments is however challenging. In this study, we employed atomic force microscopy (AFM)-based force-distance curve to study the relaxation dynamics and the film thickness dependence of glass transition temperature (T ) for normal thin polystyrene (PS) films supported on silicon substrate. The adhesion force (F) between AFM tip and normal thin PS film surfaces was quantitatively detected in situ under the variation of temperature and film thickness. The T of normal thin PS film was successfully obtained by the abrupt variation of F under temperature stimulation. Our result showed that the T of normal thin PS films decreased with the decreasing film thickness. The study here could be beneficial for understanding the relaxation dynamics of normal thin polymer films.
聚合物薄膜的松弛行为对温度和薄膜厚度有很强的依赖性。然而，用传统仪器直接在纳米尺度上定量检测聚合物薄膜的松弛行为具有挑战性。在本研究中，我们采用基于原子力显微镜（AFM）的力-距离曲线来研究硅基支撑的普通聚苯乙烯（PS）薄膜的松弛动力学以及玻璃化转变温度（Tg）与薄膜厚度的关系。在温度和薄膜厚度变化的情况下，原位定量检测了AFM针尖与普通PS薄膜表面之间的粘附力（F）。通过温度刺激下F的突变成功获得了普通PS薄膜的Tg。我们的结果表明，普通PS薄膜的Tg随薄膜厚度的减小而降低。本研究有助于理解普通聚合物薄膜的松弛动力学。
