Asymmetric Morphology Transformation of Azo Molecular Glass Microspheres Induced by Polarized Light
Asymmetric Morphology Transformation of Azo Molecular Glass Microspheres Induced by Polarized Light
复制标题
偏振光诱导偶氮分子玻璃微球的不对称形貌转变
DOI：
10.1021/acs.langmuir.9b02882
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发表时间：
2019-11-26
期刊：
影响因子：
3.9
通讯作者：
Wang, Xiaogong
中科院分区：
文献类型：
--
作者：
Huang, Hao;Su, Yechao;Wang, Xiaogong
本论文研究了一类偶氮分子玻璃微球的光诱导非对称形貌转变，探讨了控制因素对这一过程的影响、相关机理和独特功能。采用微流控技术，以异山梨醇偶氮化合物（IAC-4）为原料，制备了粒径在10 μ m以上的单分散微球。在线性偏振光照射下，通过定向传质将10微米级微球转化为三维（3D）非对称颗粒。采用显微观察和光学模拟方法研究了其形貌变化。结果表明，不同波长的光的穿透深度对IAC-4微球的非对称变形行为有着极其重要的影响，它决定了IAC-4微球的变形区域、变形程度和最终形状。光强度（50-200 mW/cm（2））是不太重要的因素，而光穿透部分的变形率随强度线性增加。当光强度在该范围内变化时，变形程度和最终的非对称形态由曝光能量（光强度x照射时间）决定。不同粒径的IAC-4微球表现出不同的形态转变行为，变形后的颗粒形状也不同，这是由于微球中透光部分体积分数的变化造成的。光穿透部分与微球总体积的比率的增加导致更大规模的变形。基于上述认识，可以通过精确可控的方法制备出各种形貌的非对称粒子。负载在各种表面上的非对称颗粒显示出使水滴在基底上的润湿各向异性显著的能力。
In this work, photoinduced asymmetric morphology transformation of a type of azo molecular glass microspheres was thoroughly investigated to understand the effects of controlling factors on the process, related mechanism and unique functions. The monodispersed microspheres with their sizes over ten microns were fabricated from an isosorbide-based azo compound (IAC-4) by microfluidics. Under irradiation with linearly polarized light, the ten-micron-scale microspheres were transformed into three-dimensional (3D) asymmetric particles through directional mass transfer. Microscopic observations and optics simulation were employed to investigate the morphology transformations. The results show that the penetration depth of light at different wavelengths plays an extremely important role to affect the asymmetric deformation behavior of the IAC-4 microspheres, which determines deformation region, deformation degree and final shapes of the particles. The light intensity (50-200 mW/cm(2)) is a less important factor, while the deformation rate of the light-penetrated part linearly increases with the intensity. When the light intensity varies in this range, the deformation degree and the final asymmetric morphology are determined by exposure energy (light intensity x irradiation time). The IAC-4 microspheres with different sizes show distinct morphology transformation behavior and the deformed particles possess different shapes, caused by the variation of volume fraction of the light-penetrated part in the microspheres. The increase in the ratio of the light-penetrated part to the total volume of the microspheres results in larger scale deformations. Based on the above understanding, asymmetric particles with various morphologies can be fabricated through a precisely controllable way. The asymmetric particles loaded on various surfaces show ability to render remarkable wetting anisotropy of water droplets on the substrates.