TAILORING THE MICRO- AND MESO-POROSITY OF SPHERICAL SILICA PARTICLES USING NANO/MICROBUBBLES AS TEMPLATES

诸如储氢、分离、催化、难溶药物输送等应用都需要内部微孔或介孔无机材料，这些材料对孔尺寸和可用表面积有特定的要求，可以可靠、容易和廉价地生产。因此，迫切需要改进现有的多孔材料的制备方法。该方案旨在通过实验研究以纳米/微泡为模板材料的全新的微孔和介孔二氧化硅颗粒。最近发表的关于纳米/微泡在水和有机溶剂中的稳定性和长寿命的研究进展为其在各个领域的应用铺平了道路，拟议的研究旨在利用稳定的纳米/微泡来调节无机材料的内部孔隙率/结构。这项工作的目的是确定影响纳米/微泡尺寸的主要参数，并将其与所产生的内部结构以及那些影响二氧化硅颗粒尺寸和均匀性的参数相关联。将使用一种有效的方法(超声波声化器和空化文丘里管)来产生纳米/微泡，并将验证它们的大小和稳定性，以便将它们用作二氧化硅液滴的模板材料，以定制球形二氧化硅颗粒的内部结构。利用膜乳化技术改进纳米/微泡二氧化硅微滴的生产，将是朝着减少表面活性剂模板法和缓慢批量操作生长二氧化硅颗粒的方向迈出的一大步。目的是促进开发一种生态友好的工艺(不依赖于模板表面活性剂)来生产高度均匀的多孔球形二氧化硅颗粒。尽管二氧化硅将被用作案例研究材料，但该工艺有可能应用于定制无机和聚合物纳米结构的内部结构。这种纳米结构在药物输送、能量(如氢)存储以及催化剂载体等方面具有巨大的应用潜力。

Applications such as hydrogen storage, separation, catalysis, delivery of poorly soluble drugs all demand internally micro- or meso-porous inorganic materials, with specific requirements for pore size and available surface area, which can be produced reliably, easily and cheaply. Therefore there is a great need to improve existing methods for production of porous materials.The proposal aims to investigate, by experiment, entirely novel micro- and meso-porous silica particles using nano/microbubbles as templating material. Recently published developments on the stability and long life of nano/microbubbles in aqueous and organic solvents have paved the way for their application in various fields and the proposed research intends to use stable nano/microbubbles to tune the internal porosity/architecture of an inorganic material. The work aims to identify the main parameters influencing the nano/microbubble size and relate it to the resulting internal structure as well as those influencing the silica particle size and uniformity. An efficient method (ultrasound sonicator and cavitation venturi tube) will be used to generate the nano/microbubbles and their size and stability will be validated allowing their use as templating material within the silica droplets to tailor the internal structure of spherical silica particles. Improved production of silica droplets containing nano/microbubbles using membrane emulsification will be a significant leap toward reducing surfactant templating methods and slow batch operation to grow silica particles.The aim is to facilitate the development of an eco-friendly process (that does not rely on templating surfactants) for the production of highly uniform porous spherical silica particles. Although silica will be used as a case study material, the process has the potential to be applied to tailor the internal architecture of both inorganic and polymeric nanostructures. Such nanostructures have great potential for applications in drug delivery, energy (e.g. hydrogen) storage as well as catalyst supports.