In situ fabrication of thermoreversible microgels

We have developed a novel in situ fabrication procedure for stimuli-responsive microgels that can respond to an external trigger. Microgels were produced by devising a novel lithographically assisted, synchrotron-radiation-induced polymer synthesis strategy. Microgel structures based on N-isopropylacrylamide, a thermoreversible hydrogel were prepared using this technique. The morphology of these gels was found to be richly nanostructured and is reversibly responsive to a temperature change, as observed from small angle neutron scattering measurements. The pore size changes reversibly from 540 nm at room temperature (25/spl deg/C), to 390 nm at 45/spl deg/C. Due to their size and synthesis method, these stimuli-responsive microgels can be used as in situ sensors, actuators, micro drug delivery systems, or size-based separation units.