Role of chain architecture in the solution phase assembly and thermoreversibility of aqueous PNIPAM/silyl methacrylate copolymers

Abstract

Thermoresponsive polymers with localized reactive inorganic groups demonstrate controlled structure formation, unique optical responses, and improved thermoreversibility during heating/cooling.

Cosolvent incorporation modulates the thermal and structural response of PNIPAM/silyl methacrylate copolymers

“…The polymers used in this work were synthesized as described in a previous report by Linn et al 32 Detailed polymer characterization data is available in the ESI of that manuscript and in ESI1.1. † Briefly, reversible addition-fragmentation chain transfer polymerization was used to synthesize polymers of controlled molecular weight and dispersity.…”

“…To enable greater control over the transition temperatures and structuring at high temperatures of PNIPAM, a change in the responsive moiety 1 or copolymerization can be used. [32][33][34] Beyond altering the polymer chemistry and structure, external additives can alter the thermal response and structuring of aqueous PNIPAM. Common additives include salts, surfactants, and organic small molecules.…”

“…Prior work from Linn et al 32 investigated PNIPAM copolymers with 3-(trimethoxysilyl)propyl methacrylate (TMA) as a route for controlling the structure size. A critical advantage to this system is that the TMA group enables post-synthetic surface grafting and inter-chain crosslinking, which is critical in numerous applications to stabilize the polymer structures and prevent structural breakup into single polymer chains.…”

“…[50][51][52] Even with the approach of copolymerization, copolymers containing TMA often display poor thermal reversibility due to the intermolecular silane crosslinking, in effect, any thermal response from the PNIPAM components of a P(NIPAM-co-TMA) copolymer is limited to only one cycle. Linn et al 32 demonstrated that localizing the TMA-containing polymer to one chain end can lead to greater cyclability in copolymers of NIPAM and TMA, which could be advantageous in applications requiring responses over multiple thermal cycles. Additionally, in contrast to random copolymers, which formed large and disperse structures (E200-400 nm) at high temperatures, polymers with localized TMA formed small, uniform micellar structures (E100-200 nm).…”

Preparation, Characterization, and Performance of a Modified Polyacrylamide-Sericite Gel

“…After introducing temperature-resistant inorganic substances into the polymer gel system, the performance of copolymer gels was significantly improved. Commonly used inorganic materials mainly include inorganic silicate [ 8 ], SiO 2 [ 9 , 10 , 11 ], kaolin [ 12 ], laponite [ 13 ], bentonite [ 14 ], sepiolite [ 15 ], attapulgite clay [ 16 ], copolymers with comonomers having precursor moieties to form silica crosslinkers by a sol-gel process [ 17 , 18 , 19 ], etc. [ 20 , 21 , 22 , 23 ].…”