Effects of pH and temperature on assembly of multiresponsive Janus microgels

Multiresponsive behaviors of Janus microgels whose properties of both hemispheres are different are presented. We fabricated the multiresponsive Janus microgels by post-polymerization modification at an oil/water interface. To prevent the microgels from wobbling at the interface during the modification process, oil droplets stabilized by microgels were solidified by cooling. Temperature- and pH-responsive behaviors of Janus microgels were characterized both by dynamic light scattering and by optical microscopy. By changing temperature and pH, behaviors of Janus microgels could be controlled; they dispersed individually or assembled into specific structures. The stimuli-responsive behaviors of Janus microgels may be used as microactuators or candidates in developing more precisely controlled particle clusters.