梳型聚合物液晶的介电反应

DIELECTRIC RESPONSE OF COMB-LIKE POLYMER LIQUID CRYSTAL

计算了梳型聚合物双轴丝状相液晶侧链的扭曲缺陷能 ,对处于外电场的侧链 ,将其哈密顿量与一维Ising模型相比较 ,得到侧链在外电场中的极化率 .结果表明 ,聚合物的电极化率远大于普通液晶 .在低温下 ,两者之间的比值趋于聚合度N .对弛豫时间的计算表明 ,聚合物液晶的极化达到饱和的时间很长 ,在低温下是普通液晶的N倍 ,而介电损耗出现的频率则为普通液晶的 1/N倍 .

Comparing the Hamiltonian of side chains in comb\|like polymer liquid crystal (LC) in external field with that of one\|dimensional Ising model,we obtain the dielectric response of polymer LC. It is shown that the ratio between the susceptibility of polymer LC and that of ordinary LC approaches to the degree of polymerization N at low temperatures. The relaxation time of side chains in external step field is much longer than that of ordinary LC while the frequency at which the maximum dielectric dissipation occurs for polymer LC is much lower than that for ordinary LC. At low temperatures the ratio of relaxation time of polymer LC to that of ordinary LC approaches to N while the ratio of frequencies approaches N\+\{-1\}.