Polystyrene‐Silica Colloidal Janus Particles with Uniform Shapes and Complex Structures
Polystyrene‐Silica Colloidal Janus Particles with Uniform Shapes and Complex Structures
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DOI：
10.1002/ppsc.202200085
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发表时间：
2022-06
影响因子：
2.7
通讯作者：
Jianchang Xu;Jichuan Qiu;Haohui Zhang;Yuhang Hu;Younan Xia
中科院分区：
文献类型：
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作者：
Jianchang Xu;Jichuan Qiu;Haohui Zhang;Yuhang Hu;Younan Xia
具有良好控制参数的胶体Janus颗粒被寻求用于介观自组装、Pickering乳液的稳定化和多功能装置的开发等一系列应用。本文中，通过溶胀PS@SiO2核-壳球状体开发了一种用于制造具有复杂形状和结构的聚苯乙烯-二氧化硅（PS-SiO2）Janus颗粒的通用方法。当封装在刚性SiO2壳中的PS被PS的良溶剂溶胀时，溶胀引起的压力将导致作用在SiO2壳上的应力的不均匀分布，这由球体的固有对称性决定。当应力达到阈值时，溶胀的PS将优先从SiO2壳层上的赤道位置突出，形成由PS和SiO2隔室组成的T形Janus颗粒。PS部分的尺寸可以通过改变溶胀程度来控制，而SiO2部分的尺寸、形状和壳厚度由原始PS球状体和SiO2涂层决定。这种溶液相方法有望生产具有不同形状，结构和组成的Janus颗粒，用于各种应用。T形Janus颗粒可用作乳化剂以有效地稳定水包油（O/W）Pickering乳液至少35天。
Colloidal Janus particles with well‐controlled parameters are sought for a range of applications in mesoscale self‐assembly, stabilization of Pickering emulsion, and development of multifunctional devices, among others. Herein, a versatile method for fabricating polystyrene‐silica (PS‐SiO2) Janus particles featuring complex shapes and structures is developed by swelling PS@SiO2 core–shell spheroids. When the PS encapsulated in a rigid SiO2 shell is swollen by a good solvent for PS, the swelling‐induced pressure will result in an uneven distribution of stress acting on the SiO2 shell, as determined by the intrinsic symmetry of a spheroid. When the stress reaches a threshold value, the swollen PS will preferentially poke out from equatorial sites on the SiO2 shell to form T‐shaped Janus particles comprised of PS and SiO2 compartments. The size of the PS portion can be controlled by varying the extent of swelling, while the size, shape, and shell thickness of the SiO2 portion are determined by the original PS spheroids and the SiO2 coating. This solution‐phase method holds promise to produce Janus particles with diverse shapes, structures, and compositions for various applications. The T‐shaped Janus particles can serve as an emulsifier to effectively stabilize an oil‐in‐water (O/W) Pickering emulsion for at least 35 days.