A synthetic approach towards micron-sized smectic liquid crystal capsules via the diffusion controlled swelling method
A synthetic approach towards micron-sized smectic liquid crystal capsules via the diffusion controlled swelling method
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通过扩散控制溶胀法合成微米级近晶液晶胶囊的方法
DOI：
10.1039/c4py01767f
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发表时间：
2015-03
影响因子：
4.6
通讯作者：
Cheng, Stephen Z. D.
中科院分区：
文献类型：
--
作者：
Van Horn, Ryan M.;Mitrokhin, Maxim;Harris, Frank W.;Cheng, Stephen Z. D.
在这里，我们展示了一种新的合成方法对微米级聚（甲基丙烯酸甲酯）粒子封装近晶型液晶（LC）通过乳液聚合，使用扩散控制的溶胀方法。研究了不同乳化剂、种子粒子、交联剂含量、液晶含量和聚合温度对液晶胶囊尺寸和形状的影响，确定了最佳工艺条件。结果表明，聚苯乙烯颗粒是比聚（丙烯酸丁酯）种子颗粒更好的种子颗粒，但他们需要更多的时间来实现奥斯特瓦尔德熟化。通过引入高量的交联剂，LC可以完全包封而没有任何泄漏，而当聚合前LC在起始材料中的负载量高于30%时，胶囊的形状从球形变为半球形。胶囊大小为约2至10微米，具有广泛的分布，如通过扫描电子显微镜和偏光显微镜表征的。LC胶囊可以通过离心分离，并且获得窄分布的胶囊。用差示扫描量热法研究了液晶胶囊的性能，结果表明，胶囊中液晶含量高于乳液中的初始含量。
We demonstrate here a novel synthetic approach towards micron-sized poly(methyl methacrylate) particles encapsulated with smectic liquid crystals (LC) via emulsion polymerization using a diffusion-controlled swelling method. The effects of different emulsifiers, seed particles, crosslinker content, LC content and polymerization temperatures on LC capsules’ size and shape were studied to obtain the optimal conditions. The results revealed that polystyrene particles were better seed particles than poly(butyl acrylate) seed particles, yet they need more time to achieve Ostwald ripening. By introducing a high amount of crosslinking agent, the LCs can be fully encapsulated without any leakage, while the capsules’ shape changed from spheres to half-spheres when the LC loading in the starting material before polymerization was higher than 30%. The capsule size is about 2 to 10 microns with a broad distribution, as characterized by scanning electron microscopy and polarized optical microscopy. The LC capsules can be fractionated by centrifugation, and narrowly distributed capsules were obtained. The properties of the LC capsules were studied by differential scanning calorimetry, and it revealed that the LC content in the capsules was higher than the initial content in the emulsion.
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影响因子：
2.4
作者：
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通讯作者：
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影响因子：
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