Novel reversible thermoresponsive nanogel based on poly(ionic liquid)s prepared via RAFT crosslinking copolymerization

Abstract

In this study, a facile strategy for the preparation of thermo-and pH-responsive nanogels through reversible additionfragmentation transfer (RAFT) crosslinking copolymerization of ionic liquid-based monomers is demonstrated. The use of chain transfer agents (CTAs) containing carboxyl group in the RAFT polymerizations is the key to producing highly thermoresponsive nanogels. Experimental results demonstrate that the critical gelation temperature of the as-prepared nanogels can be tuned by adjusting the feed ratio of monomer and CTA. Variable temperature Fourier transform infrared measurements and control experiments indicate that hydrogen-bonding interactions between the carboxyl groups of CTAs are responsible for the thermoresponsive behaviors of poly(ionic liquid) (PIL)-based nanogels. Furthermore, PIL-based nanogels are also found to be pH-sensitive, and can be further decorated by poly(N-isopropylacrylamide) (PNIPAAm) via surface grafting polymerization. PNIPAAm-grafted nanogel aqueous solutions can be reversibly transformed into macrogels upon a change in temperature.

Supramolecular assembly of poly(ionic liquid) nanogel driven by host‐stabilized charge transfer interaction

“…As a result, the size of Np‐grafted PIL nanogel can be mediated through the feeding ratio of the monomers and the crosslinker. Similar to our previous studies, the sizes of PIL nanogels are still in a wide dispersity . DLS results also reveal that the substitution group in comonomers (VBP‐Ph/Bu) has little influence on the size of Np‐grafted PIL nanogel.…”

“…In the light of broadly tunable structure of ILs, we also find that it is feasible to prepare stimuli‐responsive PIL nanogels by introducing different functional groups into IL monomers. The as‐formed PIL nanogels are of the stimuli responses including light, redox, temperature, and pH . Herein, novel PIL nanogel functionalized by naphthyl (Np) was synthesized via the as‐reported one‐step technique.…”

Temperature-Responsive Ionic Liquids: Fundamental Behaviors and Catalytic Applications

“…PIL consisting of IL 1benzyl-4-vinylpyridine bromide (4-VPBn + Br − ) and thermoresponsive polymer NIPAM has been synthesized by Wu et al 316 Thermo-responsive nanogels through reversible additionfragmentation transfer (RAFT) cross-linking copolymerization (one of several kinds of reversible-deactivation radical polymerization) of IL−based monomers is demonstrated. 317 The use of chain transfer agents (CTAs) containing a carboxyl group in the RAFT polymerizations is the key to produce highly thermoresponsive nanogels. Experimental results demonstrate that the critical gelation temperature of the as−prepared nanogels can be tuned by adjusting the feed ratio of monomer and CTA.…”

Direct one-pot synthesis of poly(ionic liquid) nanogels by cobalt-mediated radical cross-linking copolymerization in organic or aqueous media

“…[62][63][64] To the best of our knowledge, however, there is only one example that has described the synthesis of PIL nanogels by RCC, using RAFT polymerization in this case. 65 Shapepersistent PIL nanogels could be of practical interest, for instance, as additives in coatings or as membranes for CO 2 capture or in highly value added applications, e.g. in medical diagnostic tests, antibody purifications, or drug delivery systems.…”