RESUMO
Multi-purpose amphiphilic branched copolymer surfactants can be used to simultaneously stabilise and cross-link emulsion droplets to produce encapsulated spheres and hollow capsules.
Assuntos
Polímeros/síntese química , Cápsulas/síntese química , Cápsulas/química , Emulsões/química , Tamanho da Partícula , Polímeros/química , Propriedades de Superfície , Tensoativos/síntese química , Tensoativos/químicaRESUMO
Subtle changes in copolymer surfactant architecture and chain-end functionality can induce diverse behaviours in pH-responsive branched copolymer-stabilized emulsions.
RESUMO
We describe a new one-pot, single-step route for the preparation of pH-responsive branched polymer nanoparticles. These polymers, which are based on the pH-responsive monomer 2-(diethylamino)ethyl methacrylate (DEA) and hydrophilic macromonomer poly(ethyleneglycol) methacrylate (PEGMA), are synthesised using a modified conventional free-radical polymerisation. Consequently, their preparation is generic, scaleable and tolerant of functionality. In aqueous solution the branched copolymers form core-shell structures at basic pH and on reducing the solution pH they become hydrated and swell, displaying similar characteristics to those of pH-responsive shell cross-linked micelles and microgels. We demonstrate good control over the hydrodynamic particle size, polymer chain-end, and the uptake and release of a model hydrophobe and also the ability to tune the apparent pKa of the DEA residues by varying the degree of branching. These results augur well for commercially viable tunable release applications.
