Highly crosslinked functional polymer microspheres using controlled radical precipitation polymerisation

摘要

In recent years there has been growing interest in highly crosslinked, uniform polymer particles with functional groups on the particle surface, particularly for applications such as chromatographic packing materials, spacers for liquid crystal displays, synthetic receptors, controlled drug release vehicles and carriers for catalysts and enzymes. Focus has fallen particularly on precipitation polymerisation coupled with the controlled radical polymerisation techniques. Several precipitation polymerisation techniques have been employed to prepare uniform crosslinked polymer particles and two strategies have been developed as a means of preparing functional microspheres: copolymerisation of monovinyl-functional monomers with crosslinkers (which involves time-consuming optimisation of the polymerisation conditions) and grafting functional polymer layers onto the crosslinked microsphere. This latter option can also be achieved by two strategies: (a) a 'grafting to' approach, via attachment of a preformed functional polymer chain with an active terminal group that can react with a functional group on the particle surface; and (b) a 'grafting from' approach using either ionic polymerisation or controlled radical polymerisation to form well-defined, thick and dense polymer brushes.