Thickness of the Surface Mobile Layer with Accelerated Crystallization Kinetics in Poly(ethylene terephthalate) Films: Direct Measurement and Analysis
Thickness of the Surface Mobile Layer with Accelerated Crystallization Kinetics in Poly(ethylene terephthalate) Films: Direct Measurement and Analysis
复制标题
聚对苯二甲酸乙二醇酯薄膜中具有加速结晶动力学的表面移动层的厚度：直接测量和分析
DOI：
10.1021/acs.macromol.8b00396
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发表时间：
2018-04
期刊：
影响因子：
5.5
通讯作者：
Tsui Ophelia K C
中科院分区：
文献类型：
--
作者：
Xu Jianquan;Li Yun;Wu Xiaoling;Zuo Biao;Wang Xinping;Zhang Wei;Tsui Ophelia K C
超薄聚合物薄膜在自由表面附近呈现出一种液体状的可移动表面层，这对聚合物纳米材料的尺寸依赖性物理性质起着重要作用。大多数研究集中在与节段弛豫相关的表面层厚度上，而对大规模节段重排（如结晶和扩散）的研究较少。本文通过对聚对苯二甲酸乙酯薄膜的分步结晶行为的研究，对具有加速结晶动力学的表面可移动层厚度进行了简单的测量。采用椭偏法或x射线反射法测定表面结晶层厚度（hscry），并将其作为表面可移动层厚度。当温度从343 K增加到373 K时，hscry从4 nm增加到13 nm，而与分子量和膜厚度无关，这与研究人员的理论预测相吻合。
Ultrathin polymer films exhibit a liquidlike mobile surface layer near the free surface, which plays an important role in the size-dependent physical properties of polymer nanomaterials. Most research has focused on the thickness of the surface layer related to segmental relaxation, while few studies have focused on that related to large-scale segmental rearrangement, such as crystallization and diffusion. In this paper, a simple measurement of the surface mobile layer thickness with accelerated crystallization kinetics in a poly(ethylene terephthalate) film was performed by examining the stepwise crystallization behavior. The thickness of the surface crystallization layer (hscry) was determined by ellipsometry or X-ray reflection and was taken as the surface mobile layer thickness. hscry was observed to increase from 4 to 13 nm when the temperature increased from 343 to 373 K without any dependence on the molecular weight or film thickness, which fits well with the theoretical prediction by the cooperati...