基于微流体技术制备结构非均匀无机微球和催化剂的研究

The supported catalysts are prepared in the form of uniformly and non-uniformly distributed active components depending on the specific catalytic reactions. For the latter, such as hen egg-white, egg-shell and egg-yolk type catalysts, complicated preparation techniuqes and tricks have to be commanded. The newly developed microencapsulated catalysts exhibit advantages in shape-selectivity and easy recycling of active component, nevetheless, multi-steps have to be used and the inorganic shell materials are limited to zeolites, silica and carbon. In this proposal, we propose a novel microfluidic-assisted method to prepare non-uniformly distributed structured microspehres, such as core/shell and multi-core/shell structured materials or microcapsulates, based on our new finding of two aqueous phase separation in microchannel to form core/shell structured droplet, combining with the microdroplet fusion and interface reaction method. This synthetic method will provide a new thought for preparing microcapsule catalyst and active component non-uniform distributed catalysts. We will examine the similar phase separation process of the sol-containing two aqueous phase system in microchannels, the effect of the sol composition and concentration and the flow rate of the aqueous and oil phases, and the fusion of the droplets containing different types of sols. We will develop the method for introducting the catalytic active component in situ to the exact position of the microspheres. We will investigate the interfacial reaction between the aqueous core/shell structured microdroplets and the oil phase containing a reactive precursor. we will develope method to transform sol rapidly to gel. Based on the above work, we can prepare several types of non-uniformly distributed structured microspehres, such as core/shell and multi-core/shell structured materials or microcapsulates. This work can also provide a theoretical base as well as a new method and new technique to prepare microspheres with non-uniformlly distributed structures and catalysts with non-uniformlly distributed active components.

负载型催化剂根据反应的具体要求，常被制备成活性组分均匀或非均匀分布的形式。对于后者而言，其制备过程较为复杂，需要较高的操作技巧与制备工艺。新近开发的微胶囊催化剂在择形催化和活性组分的回收利用方面有明显的优势，但其制备方法较为复杂且无机壳层材料类型较为单一。本项目提出利用微通道中双水相体系微相分离形成核壳结构液滴的新发现，结合微流体液滴融合与相界面反应等技术，将载体制备成组成与结构非均匀分布的微球，为简单可控地制备活性组分非均匀分布催化剂和微胶囊催化剂提供新思路。研究微通道中双水相溶胶体系中的相分离过程，考察溶胶组成、浓度以及两相流速等对分相过程以及液滴融合的影响；探讨催化活性组分原位定点引入的方法，考察活性组分的引入对聚合分相以及界面反应的影响；开发溶胶快速凝胶方法，完成核壳以及多重核壳结构微球的制备，为活性组分非均匀分布催化剂和微胶囊催化剂的制备提供理论基础与新的技术。

负载型催化剂根据反应要求，常被制备成活性组分均匀或非均匀分布的形式。对于后者而言，其制备过程复杂，需要较高的操作技巧与制备工艺。本项目利用微通道中双水相体系微相分离形成核壳结构液滴的发现，结合微流体液滴融合与相界面反应等技术，将载体制备成非均匀分布的微球，为简单可控地制备活性组分非均匀分布催化剂和微胶囊催化剂提供新方法。.本项目在AM-PEG聚合致分相的基础上，研究了AM-Al溶胶体系的分相过程及其成型机理，探讨了各种影响因素对PAM聚合物网络以及分相过程的影响，成功的制备了空心、核壳、实心结构的无机微球。但这种方法对溶胶有一定的限制，利用微通道中液滴融合技术，摆脱溶胶的限制，成功制备了核壳、空心、多核结构的无机微球，考察了不同溶胶组合对复合微球形貌的影响，以及PAM聚合物的网络性质对溶胶粒子扩散的影响；利用液滴融合技术，还制备出各向异性的PAM水凝胶、多核壳结构PAM@ZIF-8/海藻酸盐微胶囊。在中空聚糠醇微球和中空炭球的基础上，利用界面聚合技术，成功制备出了PAM@PFA微球，改变影响因素可制备中空、蛋黄蛋白结构的炭球；利用硅溶胶作为溶剂配制PEGDA溶液和DEX溶液，并将纳米活性金属粒子分散在DEX相中，然后利用微流控芯片制备出单分散性水包水（W/W/O）核壳液滴，经后处理可得到蛋黄型催化剂。.同时，针对以上技术，还制备了多孔结构的PAM微球，原位引入催化活性组分，制备多功能化的微球；与沉淀结晶相结合，制备出PAM@CaSO4、PAM@BaSO4核壳复合微球；研究了微通道中多结构PAM纤维的制备；拓展研究了三水相复杂乳液、磁操控多元液滴、非球形多重乳液等；并且将溶液换成水性聚合物制备了刺激响应嵌入型Janus微球、中空与核壳水凝胶以及多孔异形结构高分子微粒；还拓展到MOF和分子筛领域，制备出了多种中空、核壳微球。.综上所述，本项目成功制备了多种结构的无机微球，且引入活性组分，制备核壳催化剂，具有很好的催化性能，同时项目中的技术、方法、设计的装置等具有简单操作、连续生产等优势，有望投入大规模的工业生产。