Monodisperse hollow polymer microspheres having various functional groups on the shell-layer

such as carboxylic acid

pyridyl and amide

were prepared by two-stage distillation precipitation polymerization in neat acetonitrile in the absence of any stabilizer or additive

during which monodisperse poly(methacrylic acid) (PMAA) afforded from the first-stage polymerization was utilized as the seeds for the second-stage polymerization. The shell layer with different functional groups was formed during the second-stage copolymerization of either divinylbenzene (DVB) or ethyleneglycol dimethacrylate (EGDMA) as crosslinker and the functional comonomers

in which the hydrogen-bonding interaction between the carboxylic acid group of PMAA core and the functional groups of the corresponding comonomers

including carboxylic acid

amide and pyridyl

played an essential role for the formation of monodisperse core-shell functional microspheres. The hollow polymer microspheres were then developed after the subsequent removal of PMAA cores by dissolution in ethanol under basic condition. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to determine the morphology of the resultant PMAA core

functional core-shell microspheres and the corresponding hollow polymer microspheres with different functional groups. FT-IR spectra confirmed the successful incorporation of the various functional groups on the shell layer of the hollow polymer microspheres.