高分子阳离子导体的极性基效应

EFFECT OF POLAR GROUP IN CATION-CONDUCTING POLYMER

高分子阳离子导体是一类只有阳离子充作电荷载流子的高分子固体电解质,因它在直流条件下呈现稳定的离子电导率而受世界各国学者重视。作为具有实用价值的高分子电解质,阳离子导体的关键问题是室温下离子电导率太低(一般比相应的双离子导体低1—2个数量级),难以应用。因而,国内外在这方面的研究重点集中在提高离子电导率上,近年来我们利用共混,共聚和交联等手段对提高离子电导率方面做了仔细工作,其中以极性丙烯酰胺共聚方法较好,经改进后共聚物的锂离子电导率达到2.1×10^(-6)s/cm(25℃),但对极性基改进电导率的实质未经探讨,本文将在上述工作基础上对极性丙烯酰胺共聚改进导电性的实质进行详细分析,得出有益的理论数据。

Effect of polar acrylamide (AM) group on the conductivity of Li+-conducting polymers is studied, in which the conductivity data are analyzed by Vogel-Tammann-Fulcher(VTF) equation and interpreted by the configurational entropy model. The linear VTF polts revealthat there is a close correlation between ionic conductivity and segmental motion of the polymers. Polar AM groups may enhance the dissociation degree of the salt species and lower the activation energy of exchange process of the Li+-O bonds during ionic transport , but also increase the rigidity of polymer segments. As a result, ionic conductivity of the copolymers is promoted as long as AM content is below ca. 15 wt%.