Relaxation of Single Polymer Chain in Poly (Methyl methacrylate) Films under Uniaxial Extension Observed by Scanning Near-field Optical Microscopy
Relaxation of Single Polymer Chain in Poly (Methyl methacrylate) Films under Uniaxial Extension Observed by Scanning Near-field Optical Microscopy
复制标题
扫描近场光学显微镜观察单轴拉伸下聚甲基丙烯酸甲酯薄膜中单聚合物链的弛豫
DOI：
10.1021/ma2004986
复制
发表时间：
2011
期刊：
影响因子：
5.5
通讯作者：
Toshiro Masuda
中科院分区：
文献类型：
--
作者：
Toru Ube;Hiroyuki Aoki;Shinzaburo Ito;Jun-ichi Horinaka;Toshikazu Takigawa;Toshiro Masuda
用扫描近场光学显微镜（SNOM）在真实的空间观察了单轴拉伸聚甲基丙烯酸甲酯（PMMA）薄膜应力松弛过程中的单链构象。从SNOM图像直接评估分子水平上的延伸率，并与宏观应力松弛进行比较。在松弛过程的早期阶段，尽管应力降低，但整个单链保持拉伸构象。这表明应力的快速松弛是由远小于整个链长的长度尺度上的局部构象变化引起的。用Doi-Edwards模型中原始链轮廓的收缩成功地解释了实验数据。此外，链尺寸的分布函数被发现保持其形状在松弛过程中，表明构象松弛的高分子链是相当均匀的纠缠系统。
Single chain conformations during the stress relaxation process in uniaxially stretched poly(methyl methacrylate) (PMMA) films were observed in real space by scanning near-field optical microscopy (SNOM). The extension ratio at the molecular level was directly evaluated from the SNOM images and compared with the macroscopic stress relaxation. At the early stage of the relaxation process, the whole single chain retained the stretched conformation in spite of the decrease in stress. This suggests that the fast relaxation in stress is caused by the local conformational change at the length scale much smaller than the entire chain length. The experimental data were successfully explained by the contraction of the primitive chain contour in the Doi–Edwards model. Furthermore, the distribution function of the chain dimension was found to retain its shape during the relaxation process, indicating that the conformational relaxation of polymer chain is rather homogeneous in the well-entangled system.