Postpolymerization Modification: A Powerful Tool for the Synthesis and Function Tuning of Stimuli‐Responsive Polymers

Abstract

Stimuli‐responsive polymers are a type of functional polymers showing a change in their physicochemical properties in response to external stimuli, such as temperature, pH, and electrochemical potential application, and they can be used in biosensors, biomedicine, and separation technology. Postmodification of polymers plays an important role in designing stimuli‐responsive polymers in terms of their synthesis, tuning of their thermoresponsivity, and functionalization. A variety of topological polymer structures, such as a comb, sphere, and dendrimer, can be produced, and the resultant tuning of the transition temperatures and phase types (lower critical solution temperature‐ or upper critical solution temperature‐type) can be achieved. Furthermore, postmodification techniques are employed as a useful tool to functionalize precursor polymers or improve the responsive properties of the polymers, which expands the applicable fields of these polymers. In this review, click chemistry‐related reactions, the esterification reaction, and surface‐initiated polymerization are the focus as efficient postmodification reactions to produce high‐performance stimuli‐responsive polymers.

5-Methylene-1,3-dioxane-2-one: A First-Choice Comonomer for Trimethylene Carbonate

“…This functional incompatibility imposes the utilization of protecting groups, which adds protection/deprotection steps to the synthetic process (Figure ). To tackle this problem, post-polymerization modification by addition reactions (click) has emerged as a more atom- and step-economic approach . In particular, pending vinyl groups have been introduced so that functionalization can be carried out after polymerization, typically by thiol-ene reaction, without resorting to protecting groups. − …”

Synthesis of multiple stimuli-responsive degradable block copolymers via facile carbonyl imidazole-induced postpolymerization modification

“…[44][45][46] Postpolymerization modifications have been routinely used as an alternative strategy to synthesize functional copolymers bearing pendant o-nitrobenzyl groups in hydrophobic blocks. [47][48][49][50][51] For the postpolymerization modification approach, functional acrylates or methacrylates bearing activated ester groups such as N-hydroxysuccinimide (NHS) ester, p-nitrophenyl ester and pentafluorophenyl ester have been utilized as amine-reactive handles for polymer functionalization. [51][52][53][54][55][56] Although they have been reported to be effective, several challenges such as limited solvent compatibility, interference with catalytic systems, and side reactions such as hydrolysis are described, [57][58][59][60][61][62] particularly when homo-or block copolymerization is attempted.…”

Post-polymerisation approaches for the rapid modification of conjugated polymer properties

“…32 Today, very efficient transformations are available that can be used for post-polymerisation functionalisation, but so far, most of the effort has focussed on post-polymerisation functionalisation of non-conjugated polymers or on the side chains of conjugated polymers. 32,[36][37][38][39][40][41][42][43][44][45][46] Unfortunately, the optical and electronic properties of conjugated polymers are usually not significantly influenced by reactions on the side chains, which limits the usefulness of these modifications of conjugated polymers for certain applications. 47,48 However, there are now a number of reactions that meet the above requirements and take place directly on the conjugated polymer backbone or in very close proximity.…”