title: Poly(N-isopropylacrylamide) Phase Diagrams: Fifty Years of Research.
abstract: In 1968, Heskins and Guillet published the first systematic study of the phase diagram of poly(N-isopropylacrylamide) (PNIPAM), at the time a "young polymer" first synthesized in 1956. Since then, PNIPAM became the leading member of the growing families of thermoresponsive polymers and of stimuli-responsive, "smart" polymers in general. Its thermal response is unanimously attributed to its phase behavior. Yet, in spite of 50 years of research, a coherent quantitative picture remains elusive. In this Review we survey the reported phase diagrams, discuss the differences and comment on theoretical ideas regarding their possible origins. We aim to alert the PNIPAM community to open questions in this reputably mature domain.
authors.affiliation: LIPHY, Université Grenoble Alpes, 38000 Grenoble (France). avraham.halperin@ujf-grenoble.fr.|LIPHY, CNRS, 38000 Grenoble (France). avraham.halperin@ujf-grenoble.fr.
authors.forename: Avraham
authors.initials: A
authors.lastname: Halperin
authors.affiliation: Polymer Physics, Department of Materials, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093 Zurich (Switzerland) http://complexfluids.ethz.ch. mk@mat.ethz.ch.
authors.forename: Martin
authors.initials: M
authors.lastname: Kröger
authors.affiliation: Department of Chemistry, Université de Montréal, CP 6128 Succursale Centre Ville, Montréal, QC H3C 3J7 (Canada). francoise.winnik@umontreal.ca.|WPI International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan). francoise.winnik@umontreal.ca.|Laboratory of Polymer Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Helsinki (Finland). francoise.winnik@umontreal.ca.
authors.forename: Françoise M
authors.initials: FM
authors.lastname: Winnik
keywords: lower critical solution temperature; mesoglobules; metastability; tacticity; type II phase behavior