Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB, Boulder, Colorado 80309, United States.
Department of Engineering, University of Cambridge, Cambridge, England CB2 1PZ, U.K.
ACS Appl Mater Interfaces. 2023 Mar 1;15(8):11092-11098. doi: 10.1021/acsami.2c21984. Epub 2023 Feb 15.
Liquid crystalline elastomers (LCEs) are shape-changing materials that exhibit large deformations in response to applied stimuli. Local control of the orientation of LCEs spatially directs the deformation of these materials to realize a spontaneous shape change in response to stimuli. Prior approaches to shape programming in LCEs utilize patterning techniques that involve the detailed inscription of spatially varying nematic fields to produce sheets. These patterned sheets deform into elaborate geometries with complex Gaussian curvatures. Here, we present an alternative approach to realize shape-morphing in LCEs where spatial patterning of the crosslink density locally regulates the material deformation magnitude on either side of a prescribed interface curve. We also present a simple mathematical model describing the behavior of these materials. Further experiments coupled with the mathematical model demonstrate the control of the sign of Gaussian curvature, which is used in combination with heat transfer effects to design LCEs that self-clean as a result of temperature-dependent actuation properties.
液晶弹性体（LCEs）是一种形状变化的材料，能够对施加的刺激做出大变形响应。通过局部控制 LCEs 的取向，可以在空间上引导这些材料的变形，从而实现对刺激的自发形状变化。在 LCEs 中进行形状编程的先前方法利用了涉及空间变化向列场的详细记录的图案形成技术来产生片材。这些图案化的片材变形为具有复杂高斯曲率的精细几何形状。在这里，我们提出了一种替代方法来实现 LCEs 中的形状变形，其中交联密度的空间图案化局部调节预定界面曲线两侧的材料变形幅度。我们还提出了一个简单的数学模型来描述这些材料的行为。进一步的实验结合数学模型演示了控制高斯曲率的符号，这与传热效应相结合，用于设计由于温度相关致动特性而自我清洁的 LCEs。
