Emulsion-based supracolloidal materials stabilized by specifically designed branched copolymers

摘要

The possible applications of branched copolymers are far reaching because ofudtheir various combinations of functionality and architectural diversity. Moreudimportantly, the domains and chain-end functionalities of the branchedudcopolymers can be readily varied, via the simple and scalable Strathclyde route, toudoptimize/tailor the properties of the polymers for a specific application by carefuludchoice of monofunctional monomers, branching monomers, and chain transferudagents.udIn the present thesis, branched copolymers were utilized as emulsifying agents forudthe production of oil-in-water emulsion droplets. These emulsion droplets wereudused as a platform to create novel emulsion-based supracolloidal materials. Theudchemical composition and architectural structure of the branched copolymers wereudspecifically chosen to create stable emulsions and provide the correctudfunctionalities required for the application.udCalcium phosphate (CaP) microcapsules were fabricated by utilizing oil-in-waterudemulsion droplets, stabilized with branched copolymer, as templates. Theudbranched copolymer was designed to provide a suitable architecture andudfunctionality to produce stable emulsion droplets, and permit the mineralization ofudCaP at the surface of the oil droplet. These CaP capsules were made fluorescentudby post-functionalization of the CaP shell with a fluorescent conjugate.udOil-in-water emulsion droplets stabilized with Laponite clay disc functionalizedudwith pH-responsive branched copolymers were microfluidically spun intoudsupracolloidal fibers. These supracolloidal fibers can be used as a tool to deliveryudvolatile compounds in a time-controlled manner. The dried fibers created wereudlow-weight porous materials. It was also discovered that these supracolloidaludfibers can be utilized as a storage material for emulsion droplets, where emulsionuddroplets are ‘locked’ in the fiber structure under acidic condition, and are releasedudfrom the fiber upon basification of the system. The release of emulsion dropletsudfrom the fiber can be time-controlled by programming the transient acidic pHudstates of the system by combining a fast acidic promoter with a feedback-drivenudbiocatalytically controlled slow generation of base in a close system.