Degenerative chain‐transfer process: Controlling all chain‐growth polymerizations and enabling novel monomer sequences

Abstract

This manuscript is dedicated to Professor Mitsuo Sawamoto's outstanding achievements in polymer chemistry and recognizes his recent retirement from 40 years of exceptional service to Kyoto University.ABSTRACT: The use of dormant species has opened a new era in precision polymerization and has changed the concept of living polymerization. The dormant species can be exchanged into the active species via reversible termination or via reversible chain transfer. Professor Mitsuo Sawamoto has greatly contributed to the establishment of the concepts of living cationic and radical polymerizations based on the reversible activation of dormant species. This highlight, dedicated to Professor Sawamoto on his retirement from Kyoto University, provides an overview of reversible or degenerative chain-transfer (DT) processes, which are effective in controlling all chain-growth polymerizations, including radical, cationic, anionic, coordination, ring-opening metathesis, and ring-opening polymerizations. In addition, structures with novel sequences accessible only by a combination of different propagating species with a common DT agent are reviewed.

The rise of bio-inspired polymer compartments responding to pathology-related signals

“…The building blocks of compartments are polymers and copolymers that are based on a variety of hydrophobic and hydrophilic monomers, and are synthesized by various routes. [71][72][73][74][75][76][77] Depending on their chemical nature, the resulting homo-and copolymers serve to build either compartments with intrinsic stimuli-responsive properties (Table 1) or compartments with stable, non-responsive architectures that can be combined with stimuli-responsive molecules (Table 2). Conventional free radical polymerization (free RP) can be employed in the polymerization of vinyl monomers under mild conditions.…”

Thiol‐Ene Cationic and Radical Reactions: Cyclization, Step‐Growth, and Concurrent Polymerizations for Thioacetal and Thioether Units

“…Furthermore, if those different reactions occur simultaneously, the polymer properties can be arbitrarily tuned by the reactions. Indeed, in chain‐growth polymerizations, a single monomer is polymerized simultaneously through multiple propagating species with different stereo‐ or regioselectivities, resulting in unique polymers, such as random, gradient, and block or multiblock structures, which cannot be obtained by repetitive single reactions . In addition, concurrently occurring polymerizations of common monomers by different propagating species such as radicals, cations, and anions are attractive because they can dramatically widen the scope of accessible polymer structures with novel and/or tunable properties …”

“…Furthermore,ifthose different reactions occur simultaneously,t he polymer properties can be arbitrarily tuned by the reactions.I ndeed, in chain-growth polymerizations,asingle monomer is polymerized simultaneously through multiple propagating species with different stereo-or regioselectivities, resulting in unique polymers,s uch as random, gradient, and block or multiblock structures,w hich cannot be obtained by repetitive single reactions. [2][3][4][5][6][7][8][9] In addition, concurrently occurring polymerizations of common monomers by different propagating species such as radicals,c ations,a nd anions are attractive because they can dramatically widen the scope of accessible polymer structures with novel and/or tunable properties. [10][11][12][13][14][15][16][17][18] Athiol and olefin usually undergo radical addition, that is, at hiol-ene reaction, which is one of the most efficient and robust click reactions,e ither in the presence of ar adical initiator or under UV irradiation to result in the anti-Markovnikov adduct with high selectivity and high yield.…”

Thiol‐Ene Cationic and Radical Reactions: Cyclization, Step‐Growth, and Concurrent Polymerizations for Thioacetal and Thioether Units

“…Furthermore, if those different reactions occur simultaneously, the polymer properties can be arbitrarily tuned by the reactions. Indeed, in chain‐growth polymerizations, a single monomer is polymerized simultaneously through multiple propagating species with different stereo‐ or regioselectivities, resulting in unique polymers, such as random, gradient, and block or multiblock structures, which cannot be obtained by repetitive single reactions . In addition, concurrently occurring polymerizations of common monomers by different propagating species such as radicals, cations, and anions are attractive because they can dramatically widen the scope of accessible polymer structures with novel and/or tunable properties …”