Molecular architecture dependence of mesogen rotation during uniaxial elongation of liquid crystal elastomers
Molecular architecture dependence of mesogen rotation during uniaxial elongation of liquid crystal elastomers
复制标题
液晶弹性体单轴伸长过程中介晶旋转的分子结构依赖性
DOI：
10.1016/j.polymer.2021.123970
复制
发表时间：
2021
期刊：
影响因子：
4.6
通讯作者：
Aoyagi Takeshi
中科院分区：
文献类型：
--
作者：
Yasuoka Haruka;Takahashi Kazuaki Z.;Fukuda Jun-ichi;Aoyagi Takeshi
液晶弹性体（LCE）的宏观变形被认为是由弹性聚合物网络和液晶介晶单元的耦合动力学引起的。然而，LCE分子的微观动力学很难从实验中直接观察到。在这项工作中，通过分子动力学模拟进行了 LCE 单轴伸长的计算机实验。主链型和侧链型LCE的分子系统是使用粗粒度技术构建的。获得了对外力响应的应力-应变曲线，并观察到介晶沿伸长轴的取向有序参数作为对称性破缺的证据。对于主链LCE，无论分子结构的细节如何，都可以清楚地观察到软弹性。出现了应力-应变曲线的平台区域，对应于取向顺序的剧烈对称性破坏。相比之下，对于侧链 LCE，软弹性的存在/不存在高度依赖于分子结构的细节。在某些情况下，介晶的旋转受到主链和交联颗粒的局部空间约束的抑制，从而阻止了软弹性的发生。
Macroscopic deformation of liquid crystal elastomers (LCEs) has been assumed to result from the coupling dynamics of the elastic polymer network and liquid-crystalline mesogenic units. However, the microscopic dynamics of LCE molecules are extremely difficult to directly observe from experiments. In this work, in silico experiments of uniaxial elongation of LCEs were performed by molecular dynamics simulations. The molecular systems of main- and side-chain-type LCEs were constructed using coarse-graining techniques. The stress–strain curves as the response to an external force were obtained, and the orientational order parameter of the mesogens along the elongation axis was observed as evidence of symmetry breaking. For the main-chain LCEs, soft elasticity was clearly observed regardless of the details of the molecular architecture. A plateau region of the stress–strain curves appeared, corresponding to drastic symmetry breaking of the orientational order. In contrast, for the side-chain LCEs, the presence/absence of soft elasticity was highly dependent on the details of the molecular architecture. In some cases, rotation of the mesogens was inhibited by a local steric constraint by the main chain and crosslinked particles, which prevented the onset of soft elasticity.
登录
查看更多内容
影响因子：
5.5
作者：
Brannum, Michelle T.;Auguste, Anesia D.;White, Timothy J.
通讯作者：
White, Timothy J.
影响因子：
3.4
作者：
Okamoto, Tetsuya;Urayama, Kenji;Takigawa, Toshikazu
通讯作者：
Takigawa, Toshikazu
影响因子：
2.5
作者：
Fleischmann, Eva-Kristina;Ohm, Christian;Zentel, Rudolf
通讯作者：
Zentel, Rudolf
影响因子：
5.5
作者：
Skacej, Gregor;Zannoni, Claudio
通讯作者：
Zannoni, Claudio