Nanogel-like UCST triblock copolymer micelles showing large volume expansion before abrupt dissolution

Abstract

A comprehensive study of the thermally induced large expansion in volume prior to the abrupt dissociation of the micelles of a novel UCST triblock copolymer.

Synthesis and Characterization of Temperature-Responsive N-Cyanomethylacrylamide-Containing Diblock Copolymer Assemblies in Water

“…Over the past decade, the study of novel neutral UCST polymers, mainly based on (meth)acrylamide (co)polymers [7][8][9][10][11], broadened the library of available materials. Since 2012, the UCST-behavior of poly(acrylamideco-acrylonitrile) (P(Am-co-AN)) [7], a neutral statistical copolymer of acrylamide and acrylonitrile, has been revealed and since then it has been largely studied for numerous applications [12][13][14][15][16]. While it had been generally synthesized by free radical polymerization in DMSO solution, Ferji et al [17] and some of us [18] demonstrated recently that well defined P(Am-co-AN) copolymers can be synthesized directly in water, using the reversible addition-fragmentation chain transfer (RAFT) radical polymerization.…”

Thermoresponsive properties of poly(acrylamide-co-acrylonitrile)-based diblock copolymers synthesized (by PISA) in water

“…3 Indeed, the latter was largely used to engineer thermoresponsive/stimuli-responsive block copolymer systems for drug delivery purposes, cancer theranostics/chemotherapy and photoacoustic imaging. [40][41][42][43][44][45][46][47][48][49][50][51][52] It is generally obtained by radical copolymerization of acrylamide and acrylonitrile in organic solvents, mainly in dimethylsulfoxide (DMSO). Both free radical polymerization (FRP) and reversible deactivation radical polymerization (RDRP) [53][54][55][56][57][58] mechanisms -in particular the reversible addition fragmentation chain transfer (RAFT) -have been used.…”

Near-infrared light-responsive UCST-nanogels using an efficient nickel-bis(dithiolene) photothermal crosslinker

“…Below the phase transition temperature, the particle diameter increases gradually from 65 nm to around 100 nm between 10 and 40°C. In a previous study 47 , for micelles based on the same copolymer, this increase of volume before phase transition temperature was explained by the entrance of water inside nanoparticles like for UCST-nanogels. But beyond 45°C, the diameter drastically drops to values below 10 nm, corresponding to the dissociation of the micelles (see Fig.…”

“…1). The positive thermosensitivity of PAAm-co-AN is explained by formation/disruption of hydrogen bonds upon change in temperature 47,48 , and it has appealing features such as a low sensitivity of its phase transition temperature to variation of pH and/or ionic strength as well as easy tunability of its phase transition temperature by varying the molar ratio between acrylamide and acrylonitrile [49][50][51] . To crosslink UCST nanogels using photothermal NIR dye monomer, a new nickel-bis(dithiolene) complex carrying four styrene moieties at the periphery was synthesized.…”