一种新型的超离子导体(聚氧乙烯交联网络—硫氰化钠体系)电导的研究

Study on Ionic Conductivity of a New Type of Superionic Conductor Polyethylene Oxide Network Complexes with Sodium Thiocyanate

本文以甲基丙烯酸聚氧乙烯大分子单体和含有少量双端基的该大分子单体,加热聚合交联得聚氧乙烯交联网络型材料,在不同溶剂中与NaSCN络合。研究了聚氧乙烯交联网络—NaSCN体系的络合溶剂、盐浓度、大分子单体交联度等对络合物电导率的影响。发现其室温电导率比同类型线型聚合物高二个数量级以上,其高电导率主要和体系的结晶性有关。实验测得各温度的电导率数据用VTF方程处理求算了该体系的表观电导活化能E_a,其值在0.4—0.9kJ/mol之间,约为文献值的1/5。从实验获得的σ(T)、T和T_p的数据用WLF方程处理,具有很好的线性关系,说明本体系的电导与聚合物链段运动性有密切关系。

Some ethoxy polyethylene glycol monomethacrylate macromers containing small amount of dimethacrylate were synthesized by 'Macromer Technique'. They crosslinked on heating and polyethylene oxide networks were abtained. The complexes of the networks with sodium thiocyanate had a higher conductivity than that of corresponding linear polyethylene oxides by two orders (10-5Ω-1cm-1 at room temperature) .wide-angle x-ray diffraction diagrams show that the high conductivities of these complexes are related to their low crystallinty.Effects of solvent sort and salt concentration on the crystallinity of the complexes were observed. The apparent activation energies (Ea) fol conduction were calculated by vogel-Tamman-Fulcher(VTF) equation. The temperature dependence of ionic conductivity of these systems obey the WLF equation. Therefore high conductivities of these systems could be considered to be related to the chain segment mobility.