Facile Preparation of Well-Defined Uniform Hydrophilic Hairy Hollow Functional Polymer Micro- and Nanoparticles
journal contributionposted on 06.12.2019, 14:37 by Congguang Zheng, Yan Zhou, Huiqi Zhang
A facile, general, and highly efficient strategy for preparing well-defined uniform hydrophilic hairy hollow functional polymer micro- and nanoparticles by combining RAFT polymerization techniques and the sacrificial template method is described. Two synthetic routes have been developed for this purpose. The first route involves one-pot synthesis of uniform “living” poly(methacrylic acid) (PMAA) micro/nanospheres with surface-bound dithioester groups via RAFT precipitation polymerization (RAFTPP), their successive grafting of cross-linked functional polymer layers and hydrophilic polymer brushes via surface-initiated RAFT (SI-RAFT) polymerization, and rapid etching of the PMAA core by simply washing the resulting core–shell–corona-structured particles with methanol. Alternatively, such hairy hollow polymer particles can also be prepared by synthesis of uniform “living” hollow polymer particles (through controlled grafting of cross-linked functional polymer layers onto “living” PMAA particles prepared via RAFTPP and selective etching of the PMAA core by methanol washing) and their grafting of hydrophilic polymer brushes via SI-RAFT polymerization. Uniform hairy hollow polymer particles with different hydrophilic polymer brushes and hydrodynamic diameters between 0.230 and 1.524 μm were successfully prepared via above routes. In particular, they could be easily imparted with pH-/thermoresponsivity, glutathione-induced degradability, and fluorescence by simply incorporating corresponding stimuli-responsive or functional units into their shells or polymer brushes, and well-defined uniform multiple stimuli-responsive fluorescent and degradable hydrophilic hairy hollow polymer nanoparticles were readily obtained. The above strategy opens a versatile avenue for developing various advanced hierarchical hollow polymer particles of tailor-made structures and desired properties, which hold much promise in such applications as drug delivery and theranostics.