Guan Xin, Li Yunxing, Jiang Hang, Tse Ying-Lung Steve, Ngai To
Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, P. R. China.
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, P. R. China.
Chem Asian J. 2023 Oct 4;18(19):e202300587. doi: 10.1002/asia.202300587. Epub 2023 Sep 11.
Microgels are excellent emulsifiers that can self-assemble to reduce interfacial tension and form a steric barrier at an oil-water interface. Herein, we report a two-step emulsification approach to prepare oil-in-water-in-oil (O/W/O) Pickering double emulsions through the dispersion of microgels in two immiscible phases. The stabilization mechanism depends on the uneven distribution and adsorption of hydrophilic water-swollen microgels and hydrophobic octanol-swollen microgels on either outer water droplets or inner oil droplets. Our results reveal that binary microgels outperformed single microgels in terms of interfacial tension reduction and emulsion stabilization. Notably, the binary microgel-stabilized Pickering double emulsions show excellent temperature responsiveness owing to the intrinsic thermal sensitivity of microgels. Consequently, the selective and rapid release of encapsulated substances in different phases can be achieved through the adjustment of the ambient temperature.
微凝胶是出色的乳化剂，能够自组装以降低界面张力，并在油水界面形成空间位垒。在此，我们报道一种两步乳化法，通过将微凝胶分散在两个不混溶相中制备油包水包油（O/W/O）Pickering双重乳液。其稳定机制取决于亲水性水膨胀微凝胶和疏水性辛醇膨胀微凝胶在外层水滴或内层油滴上的不均匀分布和吸附。我们的结果表明，在降低界面张力和乳液稳定性方面，二元微凝胶优于单一微凝胶。值得注意的是，由于微凝胶固有的热敏感性，二元微凝胶稳定的Pickering双重乳液表现出优异的温度响应性。因此，通过调节环境温度可以实现不同相中包封物质的选择性快速释放。
