Fabrication and characterization of controllable wrinkled-surface polymer microparticles

Polymer particles with sophisticated wrinkle patterns for addressing specific functional demands have found increasing applications in many fields. Here, we describe a novel strategy to prepare controllable wrinkled-surface polymer microspheres by soap-free emulsion polymerization method via using amphiphilic 1,1-diphenylethylene-capped hydrolyzed poly (glycidyl methacrylate) (D-PGMA) as emulsifier and initiator, which simplified the emulsion system to only three components, water, monomer and D-PGMA. It was found that both cross-linked polymer network and swelling were essential to wrinkle morphology formation of polymers by carefully monitoring the structural evolution during polymerization process. Furthermore, we investigated that wrinkle wavelength and amplitude could be controlled easily not only by varying mass ratios of D-PGMA and monomer, but also by introducing different types and dosages of solvents. Scanning electron microscopy, transmission electron microscopy, and atomic force microscopy were used to characterize wrinkle phenomenological features. Besides, by combining with mercury porosimetry, the possible internal groove structures were deduced. At last, X-ray photoelectron spectroscopy was applied to further explore the relationship between chemical components and wrinkle morphology.