title: Translating Thermal Response of Triblock Copolymer Assemblies in Dilute Solution to Macroscopic Gelation and Phase Separation.
abstract: The thermal response of semi-dilute solutions (5 w/w%) of two amphiphilic thermoresponsive poly(ethylene oxide)-b-poly(N,N-diethylacrylamide)-b-poly(N,N-dibutylacrylamide) (PEO45-PDEAmx-PDBAm12) triblock copolymers, which differ only in the size of the central responsive block, in water was examined. Aqueous PEO45-PDEAm41-PDBAm12solutions, which undergo a thermally induced sphere-to-worm transition in dilute solution, were found to reversibly form soft (G'≈10 Pa) free-standing physical gels after 10 min at 55 °C. PEO45-PDEAm89-PDBAm12copolymer solutions, which undergo a thermally induced transition from spheres to large compound micelles (LCM) in dilute solution, underwent phase separation after heating at 55 °C for 10 min owing to sedimentation of LCMs. The reversibility of LCM formation was investigated as a non-specific method for removal of a water-soluble dye from aqueous solution. The composition and size of the central responsive block in these polymers dictate the microscopic and macroscopic response of the polymer solutions as well as the rates of transition between assemblies.
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY, 11764-3400, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11974, USA.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY, 11764-3400, USA.
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Hom
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11974, USA.|Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA.|Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA.
authors.forename: Oleg
authors.identifier: 0000-0001-5534-3121
authors.initials: O
authors.lastname: Gang
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY, 11764-3400, USA.
authors.forename: Surita R
authors.initials: SR
authors.lastname: Bhatia
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY, 11764-3400, USA.
authors.forename: Robert B
authors.identifier: 0000-0002-3698-3614
authors.initials: RB
authors.lastname: Grubbs
keywords: block copolymers; gels; micelles; nanostructures; self-assembly