Song Yingxu, Zhang Sumei, Kang Jian, Chen Jinyao, Cao Ya
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Sichuan University Chengdu 610065 China
RSC Adv. 2021 Aug 26;11(46):28785-28796. doi: 10.1039/d1ra04867h. eCollection 2021 Aug 23.
Poly(vinyl alcohol) (PVA) films annealed at different temperatures are used to explore the effects of the water absorption on the formation of PVA-iodine complexes. It's found that the higher the annealing temperature, the stronger the interaction force between PVA segments, and the smaller the free volume of the PVA films. These mainly lead to the reduction of the amount of PVA segments with a moderate degree of hydration (, PVA segments with moderate mobility), which are the major segments participating in the formation of PVA-iodine complexes. Therefore, PVA films with higher water absorption not only possess faster complexation speed and form more PVA-iodine complexes, but also increase the proportion of polyiodide ions with a longer length. Moreover, the complexation restricts the PVA segments with high mobility, resulting in the formation of the intermolecular ordered structure. The water absorption dependence may guide the dyeing process to obtain PVA polarizers with excellent optical performance.
使用在不同温度下退火的聚乙烯醇（PVA）薄膜来探究吸水率对PVA-碘络合物形成的影响。研究发现，退火温度越高，PVA链段间的相互作用力越强，PVA薄膜的自由体积越小。这些主要导致水合程度适中（即具有适度流动性的PVA链段）的PVA链段数量减少，而这些链段是参与形成PVA-碘络合物的主要链段。因此，吸水率较高的PVA薄膜不仅具有更快的络合速度，能形成更多的PVA-碘络合物，而且还会增加较长链多碘离子的比例。此外，络合作用限制了具有高流动性的PVA链段，导致分子间有序结构的形成。吸水率依赖性可为获得具有优异光学性能的PVA偏振器的染色过程提供指导。
