Thermally responsive poly (N-isopropylacrylamide) (pNIPAm)-based hydrogel particles (microgels) have been extensively studied over past few decades. We, and others, have found that assemblies of these microgels exhibit unique properties that make them useful such as nonfouling surface coatings, drug release/delivery vehicles, and sensors. In this submission, we review our efforts to develop novel water remediation systems and optical devices from pNIPAm-based microgels. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3004-3020