Thermoresponsive Triblock‐Copolymers of Polyethylene Oxide and Polymethacrylates: Linking Chemistry, Nanoscale Morphology, and Rheological Properties

Marcelo Alves Da Silva,Michael T Cook,Lionel Porcar,Stewart B Kirton,Cécile A Dreiss,Peter Haddow,William J Mcauley

doi:10.1002/adfm.202109010

Marcelo Alves Da Silva, Michael T Cook + Show 5 more

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https://doi.org/10.1002/adfm.202109010

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Abstract

AbstractThermoreversible gels switch from a free‐flowing liquid state to an elastic gel mesophase upon warming, displaying the reverse transition upon cooling. While this phenomenon makes these advanced materials highly attractive in numerous fields, the generation of optimal materials of tailored rheology and transition temperatures is stifled by the lack of design principles. To address this need, a library of ABA copolymers has been prepared with “A” blocks exhibiting thermoresponsive behavior and “B” blocks of poly(ethylene glycol). This library evaluates the effect of “A” chemistry, probing three polymer classes, and A/B block molecular weight on thermally‐induced phase changes in solutions of the polymers. An exploration by rheometry coupled to Small‐Angle Neutron Scattering (SANS) elucidates temperature‐dependent hierarchical self‐assembly processes occurring on the nanoscale as well as bulk rheology. This process deciphered links between rheology and supracolloidal assemblies (sphere, ellipses, and cylinders) within the gel state with interactions probed further via structure factors. Several design principles are identified to inform the genesis of next‐generation thermoreversible gels, alongside novel materials exhibited thermoresponsive behavior in the solution state for use in applied healthcare technologies.

Highlights

The materials are being extensively explored for cell culture, tissue engineering and bioprintingThe induction of phase changes with temperature as a stimulus applications due to the induction of gel formation under mild can enable triggering of material adaptations by mild warming conditions which are less hazardous to cells than chemical cross-linkers.[7,8,9] The most commonly reported thermorevers-L
ABA triblock copolymers consisting of lower critical solution temperatures (LCSTs)-exhibiting PNIPAM, PDEGMEMA, or poly(2-N-(dimethylamino)ethyl methacrylate) (PDMAMA) “A” blocks and PEG “B” blocks exhibit a temperature-induced increase in viscosity in aqueous solution
SANS measurements indicate that the nanostructures present in solution depend both on the chemistry of the LCST polymer and the molecular weight of the constituent blocks

Summary

Introduction

The materials are being extensively explored for cell culture, tissue engineering and bioprintingThe induction of phase changes with temperature as a stimulus applications due to the induction of gel formation under mild can enable triggering of material adaptations by mild warming conditions which are less hazardous to cells than chemical cross-linkers.[7,8,9] The most commonly reported thermorevers-L. The materials are being extensively explored for cell culture, tissue engineering and bioprinting. The induction of phase changes with temperature as a stimulus applications due to the induction of gel formation under mild can enable triggering of material adaptations by mild warming conditions which are less hazardous to cells than chemical cross-linkers.[7,8,9] The most commonly reported thermorevers-. L. Porcar Institut Laue Langevin ible gelator is poloxamer 407 (or Pluronic F127), poly(ethylene oxide)100-b-poly(propylene oxide)65-b-poly(ethylene oxide)100, this material has several drawbacks, including low gel strengths for applications under shear,[10] highly concentrationdependent Tgel,[4,11] and rapid dissolution in excess fluid.[12]. Dreiss Institute of Pharmaceutical Science King’s College London Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK

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