Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University , Xi'an 710119, P. R. China.
Langmuir. 2017 May 30;33(21):5223-5235. doi: 10.1021/acs.langmuir.7b00346. Epub 2017 May 17.
The combination of an emulsion template with polymerization is a very convenient approach to the one-step realization of both simple control porous structures via a change in emulsion formulation and easy functionalization via the concomitant choice of an on-demand monomer. A major challenge of this approach is the inherent instability of the oil/water interface in emulsions, especially the occurrence of chemical reactions in oil or aqueous phases. This study reports the pioneering preparation of highly interconnected macro-mesopores and multicompartment (HIMC) vinyl organosilica microspheres with hydrophobicity by the one-step formation of W/O/W emulsions acting as a template. The emulsion system consists of acidified deionized water, a stabilizer, and vinyltriethoxysilane (VTEO) in which VTEO can be used to produce an organosilica skeleton of the resultant microsphere by a sol-gel process. The study demonstrated that the marvelous stability of W/O/W emulsions aids the formation of multicompartment organosilica microspheres with highly interconnected macro-mesopores by emulsion droplets rather than single-compartment (SC) microspheres. Meanwhile, the internal porous structure and surface morphology of as-prepared organosilica microspheres could be largely tuned by a simple variation of the pH value, the volume fraction of the water phase, and the stabilizer concentration in the initiating multiemulsions. Benefiting from such a well-orchestrated structure and the existence of numerous vinyl groups on the surface, HIMC organosilica microspheres exhibit very high hydrophobicity (with a water contact angle larger than 160°), which allows them to stabilize liquid marbles with excellent stability and high mechanical robustness. Because of its strong catalyst, Ag nanoparticles within HIMC organosilica microspheres enable Ag/HIMC-vinyl organosilica microsphere-based liquid marbles to be an efficient catalytic microreactor, realizing the complete degradation of MB to leuco methylene blue by NaBH in 10 min. The result of this work could provide some guidance for the easy, low-cost, benign preparation of HIMC microspheres having the potential to be excellent supporter of metal nanoparticles or other functionalized compounds for applications in sensing, optoelectronics, and catalysis.
乳液模板与聚合的结合是一种非常方便的方法，可以通过改变乳液配方来一步实现简单控制多孔结构，并且可以通过同时选择按需单体来轻松进行功能化。这种方法的一个主要挑战是乳液中油/水界面的固有不稳定性，特别是油相或水相中的化学反应的发生。本研究报告了通过 W/O/W 乳液的一步形成作为模板，先驱制备具有疏水性的高度互联的大介孔和多隔室（HIMC）乙烯基有机硅微球。乳液体系由酸化去离子水、稳定剂和乙烯基三乙氧基硅烷（VTEO）组成，其中 VTEO 可通过溶胶-凝胶过程用于生成所得微球的有机硅骨架。研究表明，W/O/W 乳液的出色稳定性有助于通过乳液液滴形成具有高度互联的大介孔的多隔室有机硅微球，而不是单隔室（SC）微球。同时，通过简单改变引发多乳液中的 pH 值、水相体积分数和稳定剂浓度，可以在很大程度上调节制备的有机硅微球的内部多孔结构和表面形态。得益于这种精心设计的结构和表面上存在的大量乙烯基，HIMC 有机硅微球表现出非常高的疏水性（接触角大于 160°），这使其能够稳定具有极好稳定性和高机械强度的液滴。由于其强催化剂，Ag 纳米颗粒在 HIMC 有机硅微球内使 Ag/HIMC-乙烯基有机硅微球基液滴成为高效的催化微反应器，实现了在 10 分钟内通过 NaBH 将 MB 完全降解为次甲基蓝。这项工作的结果可为轻松、低成本、良性制备 HIMC 微球提供一些指导，这些微球具有成为金属纳米颗粒或其他功能化化合物的优秀载体的潜力，可应用于传感、光电和催化领域。
