Permanent and reversibly programmable shapes in liquid crystal elastomer microparticles capable of shape switching
Permanent and reversibly programmable shapes in liquid crystal elastomer microparticles capable of shape switching
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DOI：
10.1039/d0sm01836h
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发表时间：
2021-01-21
期刊：
影响因子：
3.4
通讯作者：
Bowman, Christopher N.
中科院分区：
文献类型：
--
作者：
Martinez, Alina M.;Cox, Lewis M.;Bowman, Christopher N.
可逆可编程液晶弹性体微粒（LCEMPs），形成为共价自适应网络（CAN），具有7 μ m +/- 2 μ m的平均直径，通过硫醇迈克尔分散聚合合成。通过光引发的加成-断裂链转移（AFT）交换反应，通过在经历压缩后激活AFT，将颗粒编程为扁长形。由于AFT-LCEMPs的热致性，通过将颗粒加热到它们的向列相-各向同性相转变温度（T-NI）以上来驱动形状切换。程序化的粒子随后显示出可循环的双向形状切换，从扁长形到球形时，在低温或高温下，分别。此外，形状编程是可逆的，并且进行第二编程步骤以通过在高温下引发AFT来擦除扁长形状，同时颗粒处于其球形形状。冷却后，颗粒保持球形，直到采取额外的编程步骤。颗粒也被编程以保持永久的扁球形。此外，用衍射光栅对颗粒表面进行编程，通过AFT活化展示可编程的复杂表面形貌。
Reversibly programmable liquid crystal elastomer microparticles (LCEMPs), formed as a covalent adaptable network (CAN), with an average diameter of 7 mu m +/- 2 mu m, were synthesized via a thiol-Michael dispersion polymerization. The particles were programmed to a prolate shape via a photoinitiated addition-fragmentation chain-transfer (AFT) exchange reaction by activating the AFT after undergoing compression. Due to the thermotropic nature of the AFT-LCEMPs, shape switching was driven by heating the particles above their nematic-isotropic phase transition temperature (T-NI). The programmed particles subsequently displayed cyclable two-way shape switching from prolate to spherical when at low or high temperatures, respectively. Furthermore, the shape programming is reversible, and a second programming step was done to erase the prolate shape by initiating AFT at high temperature while the particles were in their spherical shape. Upon cooling, the particles remained spherical until additional programming steps were taken. Particles were also programmed to maintain a permanent oblate shape. Additionally, the particle surface was programmed with a diffraction grating, demonstrating programmable complex surface topography via AFT activation.