Light-Responsive Crosslinked Polymer Particles from Heterogeneous Polymerization of an Asymmetric Divinyl Azobenzene Monomer
Light-Responsive Crosslinked Polymer Particles from Heterogeneous Polymerization of an Asymmetric Divinyl Azobenzene Monomer
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DOI：
10.1021/acsapm.3c00031
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发表时间：
2023-03-23
影响因子：
5
通讯作者：
Ihara，Eiji
中科院分区：
文献类型：
--
作者：
Itoh，Tomomichi;Kimoto，Moeka;Ihara，Eiji
偶氮苯聚合物粒子由于其有趣的光响应特性，已经被研究了二十多年。在实际应用中，交联是提高偶氮苯聚合物粒子可重用性的一种很有前途的解决方案；然而，生产交联偶氮苯粒子仍然具有挑战性。在这项研究中，开发了交联型偶氮苯聚合物颗粒，以实现光响应性、可恢复性和可重复使用。含有不对称二乙烯基团的偶氮苯单体(E)-6-(4-((4-(allyloxy)phenyl)diazenyl)phenoxy)hexyl甲基丙烯酸酯的沉淀聚合和分散聚合成功地赋予了交联型偶氮苯聚合物粒子独特的扁平形状和窄的尺寸分布。偏光显微镜研究表明，偶氮苯基团在粒子中排列，并具有双极构型。在紫外光(365 Nm)和白光照射下，颗粒呈现出可恢复的光响应形状变化。通过沉淀聚合和分散聚合分别制备了油包水和水包油的Pickering乳液，这两种乳液在光照射下均发生可逆的形成和变形。此外，还实现了光响应型液体弹珠中颗粒的可重复使用。因此，不对称二乙烯基偶氮苯单体成功地制备了可回收和可重复使用的光响应性聚合物颗粒。
Azobenzene polymer particles have been investigated for over two decades, owing to their interesting light-responsive properties. Crosslinking is a promising solution for improving the reusability of azobenzene polymer particles for practical use; however, the production of crosslinked azobenzene particles remains challenging. In this study, crosslinked azobenzene polymer particles were developed to achieve light responsiveness, recoverability, and reusability. The precipitation polymerization and dispersion polymerization of an azobenzene monomer, (E)-6-(4-((4-(allyloxy)phenyl)diazenyl)phenoxy)hexyl methacrylate bearing asymmetric divinyl groups, successfully endowed crosslinked azobenzene polymer particles with a unique oblate shape and narrow size distribution. Polarized optical microscope studies indicated that the azobenzene groups were aligned in the particles and had a bipolar configuration. The particles exhibited recoverable light-responsive shape changes upon irradiation with ultraviolet (365 nm) and white light. Hydrophobic and hydrophilic particles prepared by precipitation and dispersion polymerizations yielded water-in-oil and oil-in-water Pickering emulsions, respectively, which were both reversibly formed and deformed upon light irradiation. Furthermore, the reusability of the particles in light-responsive liquid marbles was achieved. Consequently, the asymmetric divinyl azobenzene monomer successfully produced recoverable and reusable light-responsive polymer particles.