Photoactive nematic elastomers are soft rubbery solids that undergo deformation when illuminated. They are made by incorporating photoactive molecules like azobenzene into nematic liquid crystal elastomers. Since its initial demonstration in 2001, it has received increasing interest with many recent studies of periodic and buckling behavior. However, theoretical models developed have focused on describing specific deformation modes (e.g., beam bending and uniaxial contraction) in the absence of mechanical loads, with only limited attention to the interplay between mechanical stress and light-induced deformation. This paper explores photomechanical coupling in a photoactive nematic elastomer under both light illumination and mechanical stress. We begin with a continuum framework built on the free energy developed by Corbett and Warner (Phys. Rev. Lett. 2006). Mechanical stress leads to nematic alignment parallel to a uniaxial tensile stress. In the absence of mechanical stress, in the photo-stationary state where the system reaches equilibrium, the nematic director tends to align perpendicular to the polarization of a linearly polarized light. However, sufficient illumination can destroy nematic order through a first-order nematic-isotropic phase transition which is accompanied by a snap through deformation. Combined illumination and mechanical stress can lead to an exchange of stability accompanied by stripe domains. Finally, the stress-intensity phase diagram shows a critical point that may be of interest for energy conversion.

光敏向列型弹性体是柔软的橡胶状固体，在照射时会变形。它们是通过将光活性分子（如偶氮苯）掺入向列液晶弹性体中制成的。自2001年首次演示以来，它对周期性和屈曲行为的许多最新研究都引起了越来越多的兴趣。但是，开发的理论模型集中于描述在没有机械载荷的情况下的特定变形模式（例如，梁的弯曲和单轴收缩），而对机械应力和光诱导变形之间的相互作用的关注有限。本文探讨了在光照和机械应力下光敏向列弹性体中的光机械耦合。我们从以Corbett和Warner（物理 牧师 2006）。机械应力导致平行于单轴拉伸应力的向列取向。在没有机械应力的情况下，在系统达到平衡的光平稳状态下，向列导向器倾向于垂直于线性偏振光的偏振方向排列。然而，足够的照明可以通过一阶向列各向同性的相变破坏向列序，该相变伴随有快速通过变形。结合的照明和机械应力会导致伴随条纹区域的稳定性交换。最后，应力强度相图显示了一个可能对能量转换感兴趣的临界点。