Organic Chemistry Institute/Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149, Münster.
Busso-Peus-Straße 10, 48149, Münster, Germany.
Chemistry. 2021 May 17;27(28):7667-7676. doi: 10.1002/chem.202100547. Epub 2021 May 2.
The surface chemistry of colloidal silica has tremendous effects on its properties and applications. Commonly the design of silica particles is based on their de novo synthesis followed by surface functionalization leading to tailormade properties for a specific purpose. Here, the design of robust "precursor" polymer-decorated silica nano- and microparticles is demonstrated, which allows for easy post-modification by polymer embedded thiolactone chemistry. To obtain this organic-inorganic hybrid material, silica particles (SiO P) were functionalized via surface-initiated atom transfer radical polymerization (SI-ATRP) with poly(2-hydroxyethyl acrylate) (PHEA)-poly(thiolactone acrylamide (PThlAm) co-polymer brushes. Exploiting the versatility of thiolactone post-modification, a system was developed that could be used in three exemplary applications: 1) the straightforward molecular post-functionalization to tune the surface polarity, and therefore the dispersibility in various solvents; 2) the immobilization of metal nanoparticles into the polymer brushes via the in situ formation of free thiols that preserved catalytic activity in a model reaction; 3) the formation of redox-responsive, permeable polymer capsules by crosslinking the thiolactone moieties with cystamine dihydrochloride (CDH) followed by dissolution of the silica core.
胶体二氧化硅的表面化学对其性质和应用有巨大影响。通常，二氧化硅颗粒的设计基于其从头合成，然后进行表面功能化，从而为特定目的定制特定的性质。在这里，展示了设计坚固的“前体”聚合物修饰的二氧化硅纳米和微颗粒，其允许通过聚合物嵌入硫内酯化学进行容易的后修饰。为了获得这种有机-无机杂化材料，通过表面引发原子转移自由基聚合（SI-ATRP）用聚（2-羟乙基丙烯酰胺）（PHEA）-聚（硫内酯丙烯酰胺（PThlAm）共聚物刷对二氧化硅颗粒（SiO P）进行功能化。利用硫内酯后修饰的多功能性，开发了一种可用于三个示例应用的系统：1）通过简单的分子后功能化来调节表面极性，从而在各种溶剂中调节分散性；2）通过原位形成自由硫醇将金属纳米粒子固定在聚合物刷中，在模型反应中保持催化活性；3）通过用半胱胺二盐酸盐（CDH）交联硫内酯部分，然后溶解二氧化硅核，形成氧化还原响应、可渗透的聚合物胶囊。
