Influence of Orientational Genesis on the Actuation of Monodomain Liquid Crystalline Elastomers
Influence of Orientational Genesis on the Actuation of Monodomain Liquid Crystalline Elastomers
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DOI：
10.1021/acs.macromol.1c00437
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发表时间：
2021-04-22
期刊：
影响因子：
5.5
通讯作者：
White, Timothy J.
中科院分区：
文献类型：
--
作者：
Hebner, Tayler S.;Bowman, Christopher N.;White, Timothy J.
液晶弹性体（LCE）内的指向矢的宏观排列放大了定向应变响应的幅度。理论预测，LCE的刺激反应将受到交联的取向起源的影响。我们研究组成相同的LCE对齐无论是机械或表面技术。通过机械排列制备LCE的两步程序首先形成处于无序状态的交联（例如，各向同性取向成因），其后通过变形排列，在此期间聚合（例如，交联）完成。相比之下，表面对齐的LCE内的交联仅发生在有序状态（例如，定向成因）。在组成相同的样品中，对齐的LCE中的交联的取向成因显著地影响这些材料的热致性和光致性变形。通过机械对准制备的LCE（例如，各向同性取向成因）的致动温度比通过表面配向制备的类似LCE（例如，定向成因）。同样，在偶氮苯官能化的LCE制备的机械和表面对准的光致应变产生的幅度和速率相差2倍或更大。
The macroscopic alignment of the nematic director within liquid crystalline elastomers (LCEs) amplifies the magnitude of the directional strain response. Theory predicts that the stimuli response of LCEs will be affected by the orientational genesis of cross-linking. We examine compositionally identical LCEs aligned by either mechanical or surface techniques. The two-step procedure to prepare LCEs by mechanical alignment first forms cross-links in a disordered state (e.g., isotropic orientational genesis), which thereafter are aligned by deformation during which polymerization (e.g., cross-linking) is completed. Comparatively, cross-linking within surface-aligned LCEs exclusively occurs within the ordered state (e.g., nematic orientational genesis). The orientational genesis of cross-linking in aligned LCEs, in compositionally identical samples, significantly affects the thermotropic and phototropic deformation of these materials. LCEs prepared by mechanical alignment (e.g., isotropic orientational genesis) have actuation temperatures that are as much as 75 degrees C lower than the analogous LCEs prepared by surface alignment (e.g., nematic orientational genesis). Likewise, the magnitude and rate of photoinduced strain generation in azobenzene-functionalized LCEs prepared by mechanical and surface alignment differ by a factor of 2 or greater.