Interplay between Hydrogen Bonding and Macromolecular Architecture Leading to Unusual Phase Behavior in Thermosensitive Microgels

In a depressed state: The intra- and intermolecular hydrogen-bonding pattern of microgels comprising N-isopropylacrylamide (NIPAM) and N,N-diethylacrylamide (DEAAM) can be determined by FTIR spectroscopy. In contrast to core–shell systems (see picture, right), an increase in intramolecular hydrogen bonding in copolymer microgels (left) favors polymer–polymer interactions and leads to a marked depression of the phase-transition temperature.