TY - JOUR
T1 - Thermoresponsive poly(di(ethylene glycol) methyl ether methacrylate)-ran-(polyethylene glycol methacrylate) graft copolymers exhibiting temperature-dependent rheology and self-assembly
AU - da Silva, Jéssica Bassi
AU - Haddow, Peter
AU - Bruschi, Marcos Luciano
AU - Cook, Michael T.
N1 - © 2021 The Authors. Published by Elsevier B.V. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/
PY - 2022/1/15
Y1 - 2022/1/15
N2 - Graft copolymers with brush-type architectures are explored containing poly (ethylene glycol) methacrylates copolymerized with “thermoresponsive” monomers which impart lower critical solution temperatures to the polymer. Initially, the chemical structure of the thermoresponsive polymer is explored, synthesizing materials containing N-isopropyl acrylamide, N,N-diethylacrylamide and diethylene glycol methyl ether methacrylate. Thermoresponsive graftcopolymers containing di(ethylene glycol) methyl ether methacrylate (DEGMA) exhibited phase transition temperature close to physiological conditions (ca 30 °C). The effect of polymer composition was explored, including molecular weight, PEG-methacrylate (PEGMA) terminal functionality and PEGMA/DEGMA ratios. Molecular weight exhibited complex relationships with phase behavior, where lower molecular weight systems appeared more stable above lower critical solution temperatures (LCST), but a lower limit was identified. PEGMA/DEGMA feed was able to control transition temperature, with higher PEGMA ratios elevating thermal transition. It was found that PEGMA terminated with methoxy functionality formed stablecolloidal structures above LCST, whereas those the hydroxy termini generally formed two phase sedimented systems when heated. Two thermoresponsive DEGMA-based graft polymers, poly(PEGMA7-ran-DEGMA170) and poly(PEGMA1-ran-DEGMA38), gave interesting temperature-dependent rheology, transitioning to a viscous state upon heating. These materials may find application in forming thermothickening systems which modify rheology upon exposure to the body’s heat
AB - Graft copolymers with brush-type architectures are explored containing poly (ethylene glycol) methacrylates copolymerized with “thermoresponsive” monomers which impart lower critical solution temperatures to the polymer. Initially, the chemical structure of the thermoresponsive polymer is explored, synthesizing materials containing N-isopropyl acrylamide, N,N-diethylacrylamide and diethylene glycol methyl ether methacrylate. Thermoresponsive graftcopolymers containing di(ethylene glycol) methyl ether methacrylate (DEGMA) exhibited phase transition temperature close to physiological conditions (ca 30 °C). The effect of polymer composition was explored, including molecular weight, PEG-methacrylate (PEGMA) terminal functionality and PEGMA/DEGMA ratios. Molecular weight exhibited complex relationships with phase behavior, where lower molecular weight systems appeared more stable above lower critical solution temperatures (LCST), but a lower limit was identified. PEGMA/DEGMA feed was able to control transition temperature, with higher PEGMA ratios elevating thermal transition. It was found that PEGMA terminated with methoxy functionality formed stablecolloidal structures above LCST, whereas those the hydroxy termini generally formed two phase sedimented systems when heated. Two thermoresponsive DEGMA-based graft polymers, poly(PEGMA7-ran-DEGMA170) and poly(PEGMA1-ran-DEGMA38), gave interesting temperature-dependent rheology, transitioning to a viscous state upon heating. These materials may find application in forming thermothickening systems which modify rheology upon exposure to the body’s heat
KW - Health and Wellbeing
U2 - 10.1016/j.molliq.2021.117906
DO - 10.1016/j.molliq.2021.117906
M3 - Article
SN - 0167-7322
VL - 346
SP - 1
EP - 9
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
M1 - 117906
ER -