Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
Macromol Rapid Commun. 2023 Jan;44(2):e2200547. doi: 10.1002/marc.202200547. Epub 2022 Oct 25.
Untethered small actuators have drawn tremendous interest owing to their reversibility, flexibility, and widespread applications in various fields. For polymer actuators, however, it is still challenging to achieve programmable structural changes under different stimuli caused by the intractability and single-stimulus responses of most polymer materials. Herein, multi-stimuli-responsive polymer actuators that can respond to light and solvent via structural changes are developed. The actuators are based on bilayer films of polydimethylsiloxane (PDMS) and azobenzene chromophore (AAZO)-crosslinked poly(diallyldimethylammonium chloride) (PDAC). Upon UV light irradiation, the AAZO undergoes trans-cis-trans photoisomerization, causing the bending of the bilayer films. When the UV light is off, a shape recovery toward an opposite direction occurs spontaneously. The reversible deformation can be repeated at least 20 cycles. Upon solvent vapor annealing, one of the bilayer films can be selectively swollen, causing the bending of the bilayer films with the directions controlled by the solvent vapors. The effects of different parameters, such as the weight ratios of AAZO and film thicknesses, on the bending angles and curvatures of the polymer films are also analyzed. The results demonstrate that multi-stimuli-responsive actuators with fast responses and high reproducibility can be fulfilled.
无绳小型致动器因其可恢复性、灵活性以及在各个领域的广泛应用而引起了极大的关注。然而，对于聚合物致动器来说，由于大多数聚合物材料的难以处理性和单一刺激响应，仍然难以实现不同刺激下的可编程结构变化。在此，开发了能够通过结构变化响应光和溶剂的多刺激响应聚合物致动器。该致动器基于聚二甲基硅氧烷 (PDMS) 和偶氮苯发色团 (AAZO)-交联聚二烯丙基二甲基氯化铵 (PDAC) 的双层膜。在紫外光照射下，AAZO 经历顺式-反式-顺式光异构化，导致双层膜弯曲。当紫外光关闭时，会自发地向相反方向发生形状恢复。这种可逆变形可以至少重复 20 个循环。在溶剂蒸汽退火后，其中一个双层膜可以选择性地溶胀，导致双层膜弯曲，弯曲方向由溶剂蒸汽控制。还分析了不同参数（如 AAZO 的重量比和膜厚度）对聚合物膜的弯曲角度和曲率的影响。结果表明，可以实现具有快速响应和高重复性的多刺激响应致动器。
