Study of theThermo-/pH-Sensitivity of Stereo-Controlled Poly(N-isopropylacrylamide-co-IAM) Copolymers via RAFT Polymerization

Abstract

Abstract:In this work, a smart copolymer, Poly(nipam-co-IAM) was synthesized by copolymerization of N-isopropylacrylamide (nipam) and itaconamic acid (IAM) through reversible addition-fragmentation chain-transfer (RAFT) polymerization. Poly(nipam-co-IAM) has been studied previously synthesized via radical polymerization without stereo-control, and this work used cumyl dithiobenzoate and Ytterbium(III) trifluoromethanesulfonate as RAFT and stereo-control agents, respectively. The stereo-control result in this work shows that tacticity affects the lower critical solution temperature (LCST) and/or the profile of phase separation of Poly(nipam-co-IAM). In the pH 7 and pH 10 buffer solutions, the P(nipam-co-IAM) copolymer solutions showed soluble-insoluble-soluble transitions, i.e., both LCST and upper critical solution temperature (UCST) transitions, which had not been found previously, and the insoluble to soluble transition (redissolved behavior) occurred at a relatively low temperature. The insoluble to soluble transition of P(nipam-co-IAM) in alkaline solution occurred at a temperature of less than 45 • C. However, the redissolved behavior of P(nipam-co-IAM) was found only in the pH 7 and pH 10 buffer solutions and this redissolved behavior was more prominent for the atactic copolymers than in the isotactic-rich ones. In addition, the LCST results under our experimental range of meso content did not show a significant difference between the isotactic-rich and the atactic P(nipam-co-IAM). Further study on the soluble-insoluble-soluble (S-I-S) transition and the application thereof for P(nipam-co-IAM) copolymers will be conducted.

Synthesis of a Smart Conductive Block Copolymer Responsive to Heat and Near Infrared Light

“…Other kinds of applications were the combination of those polymers to generate macroscopic composites to be used as pressure sensors and thermal switch, microwave responsive devices, and chemo-mechanical actuators [16,17,18]. In recent years, a series of copolymers based on PNIPAM were synthesized, demonstrating the versatility of this thermosensitive polymer for the development of new materials [19,20,21,22,23]. Hsiao et al [24] demonstrated that it is possible to grow PANI from the alkyl amine (R-NH 2 ) groups of chitosan producing another kind of NIR absorbing hydrogel.…”

Playing construction with the monomer toy box for the synthesis of multi‐stimuli responsive copolymers by reversible deactivation radical polymerization protocols

“…Even though they react sluggishly in FRP conditions, ATRP and RAFT have been successful at obtaining copolymers containing itaconic acid derivatives 24 . For example, pH‐ and temperature‐sensitive random copolymers of NIPAAm and itaconamic acid were obtained by RAFT in Rwei's group 240,241 . RAFT polymerization of vinyl monomers derived from renewable sources, for example aminoacids, carbohydrates, lignin, plant oils, has been recently reviewed 242 …”

Progress in the Free and Controlled Radical Homo‐ and Co‐Polymerization of Itaconic Acid Derivatives: Toward Functional Polymers with Controlled Molar Mass Distribution and Architecture

“…[ 151 ] In the field of stimulus‐responsive polymers, copolymerization of itaconamic acid and N ‐isopropylamine (NIPAM) via RAFT in was reported, which led pH‐ and thermoresponsive polymers. [ 152 ] Fluorescent copolymers were obtained from styrene and itaconic acid by photo‐initiated RAFT with a fluorophore‐bearing RAFT agent. [ 153 ] These copolymers self‐assembled into organic nanoparticles and could be loaded with the anti‐cancer drug cisplatin.…”