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A Single Thermoresponsive Diblock Copolymer Can Form Spheres, Worms or Vesicles in Aqueous Solution
Author(s) -
Ratcliffe Liam P. D.,
Derry Matthew J.,
Ianiro Alessandro,
Tuinier Remco,
Armes Steven P.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201909124
Subject(s) - copolymer , methacrylamide , methacrylate , aqueous solution , polymer chemistry , materials science , vesicle , monomer , self assembly , polymerization , volume fraction , small angle x ray scattering , degree of polymerization , rheology , micelle , polymer , chemical engineering , chemistry , nanotechnology , organic chemistry , acrylamide , scattering , composite material , membrane , biochemistry , physics , engineering , optics
It is well‐known that the self‐assembly of AB diblock copolymers in solution can produce various morphologies depending on the relative volume fraction of each block. Recently, polymerization‐induced self‐assembly (PISA) has become widely recognized as a powerful platform technology for the rational design and efficient synthesis of a wide range of block copolymer nano‐objects. In this study, PISA is used to prepare a new thermoresponsive poly( N ‐(2‐hydroxypropyl) methacrylamide)‐poly(2‐hydroxypropyl methacrylate) [PHPMAC‐PHPMA] diblock copolymer. Remarkably, TEM, rheology and SAXS studies indicate that a single copolymer composition can form well‐defined spheres (4 °C), worms (22 °C) or vesicles (50 °C) in aqueous solution. Given that the two monomer repeat units have almost identical chemical structures, this system is particularly well‐suited to theoretical analysis. Self‐consistent mean field theory suggests this rich self‐assembly behavior is the result of the greater degree of hydration of the PHPMA block at lower temperature, which is in agreement with variable temperature 1 H NMR studies.