基于分子动力学的P(VDF_(50)-TrFE_(50))高电场极化仿真

Molecular dynamics simulation of P(VDF_(50)-TrFE_(50))polarized in high electric field

P(VDF-TrFE)类共聚物具有优异的铁电性能,可用于制作柔性压电传感器。在试验研究中,通常采用高电场极化来增强其压电效应。为了研究该共聚物的传感特性,本文利用分子动力学模拟软件Materials Studio(MS)建立P(VDF_(50)-TrFE_(50))的三维晶胞模型,模拟高电场极化过程,分析各项极化条件对其剩余极化的影响。结果显示:在高电场强度下,晶胞内的大部分铁电畴在极短时间内完成翻转;P(VDF_(50)-TrFE_(50))的极化强度与外加电场强度正相关,但当电场强度高于5 V/nm后,极化强度增长减缓;晶胞在低温时保持铁电相而在高温时转变为顺电相;被充分极化的P(VDF_(50)-TrFE_(50))晶胞的最高剩余极化强度为59.94 mC/m^(2)。该研究表明MS软件具有模拟P(VDF-TrFE)聚合物材料压电特性的能力,可为后续试验研究及传感器制作提供仿真依据。

P(VDF-TrFE)copolymers have excellent ferroelectric properties and can be used to make flexible piezoelectric sensors.In experimental researches,high electric field polarization is usually applied to enhance the piezoelectric effect.In order to study the sensing characteristics of these copolymers,a three-dimensional crystal cell model of P(VDF_(50)-TrFE_(50))was established by using molecular dynamics simulation software Materials Studio(MS)to simulate the polarization process in high electric field,and the influences of various polarization conditions on the residual polarization were analyzed.The results show that most ferroelectric domains in the cell flip in an extremely short period under high electric field intensity.The polarization intensity of P(VDF_(50)-TrFE_(50))is positively correlated with the applied electric field intensity,but the increase of polarization intensity slows down when the electric field intensity exceeds 5 V/nm.Crystal cells maintain ferroelectric phase at low temperature but transform into paraelectric phase at high temperature.The maximum residual polarization of the fully polarized P(VDF_(50)-TrFE_(50))cell is 59.94 mC/m^(2).This study indicates that MS software has the ability to simulate the piezoelectric properties of P(VDF-TrFE)polymer materials,which can provide a simulation basis for the subsequent experimental researches and the fabrication of sensors.