Effect of the presence of an ordered micro-pillar array on the formation of silica monoliths

We report on the synthesis of siloxane-based monoliths in the presence of a two-dimensional, perfectly ordered array of micro-pillars. Both methyltrimethoxysilane- and tetramethoxysilane-based monoliths were considered. The obtained structures were analyzed using scanning-electron microscopy and can be explained from the general theory of surface-directed phase separation in confined spaces. The formed structures are to a large extent nearly exclusively determined by the ratio between the bulk domain size of the monolith on the one hand and the distance between the micro-pillars on the other hand. When this ratio is small, the presence of the pillars has nearly no effect on the morphology of the produced monoliths. However, when the ratio approaches unity and ascends above it, some new types of monolith morphologies are induced, two of which appear to have interesting properties for use as novel chromatographic supports. One of these structures (obtained when the domain size/inter-pillar distance ratio is around unity) is a 3D network of linear interconnections between the pillars, organized such that all skeleton branches are oriented perpendicular to the micro-pillar surface. A second interesting structure is obtained at even higher values of the domain size/inter-pillar distance ratio. In this case, each individual micro-pillar is uniformly coated with a mesoporous shell.     

采用超疏水微柱阵列模板法制备多糖凝胶微米颗粒

开发了一种制备尺寸均一的多糖基微凝胶(PsMH)的新方法:以超疏水、高黏附的微米级圆柱状结构硅基底为模板,通过在微柱结构顶端黏附微液滴,并在挥发过程中紫外固化,制备了扁平状的PsMH.研究发现,采用此方法制备的PsMH尺寸均一,且均匀分布在微柱顶端.通过改变凝胶预聚液浓度及微柱直径,可以有效调节PsMH的尺寸.这种多糖基微凝胶有望应用于药物递送及纳米粒子载体等方面.