Thermoresponsive core–shell nanoparticles with cross-linked π-conjugate core based on amphiphilic block copolymers by RAFT polymerization and palladium-catalyzed coupling reactions

Synthesis of sulfur-containing alternating copolymers by RAFT copolymerization of phenyl vinyl sulfides

“…These results suggest that the trithiocarbonate-type CTA 3 is effective in controlling the alternating copolymerization, which is dominant because of the participation of charge-transfer complexes or donor-acceptor interaction. In our previous work [32], we concluded that the combination of the bulky tertiary alkyl group with the electron-withdrawing cyano group (-C(CH 3 ) 2 CN) in CTA 3 provided a good balance between the leaving and reinitiation abilities of the RAFT polymerization of PVS; this might be also critical to the success of alternating copolymerization containing PVS. Here, it must be noted that the mechanism of alternation in donor-acceptor copolymerization is still under debate, and there are three main proposed mechanisms: the terminal model, the penultimate model, and the complex model [4].…”

“…In this study, three mediating agents with different Z groups, O-ethyl-S-(1-ethoxycarbonyl) ethyldithiocarbonate (CTA 1), benzyl 1-pyrrolecarbodithioate (CTA 2), and 2-cyano-2-propyl dodecyl trithiocarbonate (CTA 3), were selected as CTAs. Recently, we reported the efficiency of these three CTAs in achieving a controlled nature of RAFT polymerization of S-vinyl sulfide derivatives [31][32][33], in spite of the significant difference in the chain transfer constants, which may be because of the intermediate reactivity between the conjugated and nonconjugated monomers of the S-vinyl sulfides. The xanthate-type CTA (CTA 1), which is known to be useful in controlling the radical polymerization of nonconjugated O-vinyl and N-vinyl monomers [57], allowed for the synthesis of block copolymers composed of N-vinyl carbazole and S-vinyl sulfides [31].…”

“…By contrast, the synthesis of PVS-based block copolymers composed of styrene was achieved using the trithiocarbonate-type CTA 3 [33], which has been used in the controlled RAFT polymerization of conventional conjugated monomers [1,47]. Amphiphilic block copolymers composed of S-vinyl sulfides and N-isopropyl acrylamide were synthesized by the dithiocarbamate-type CTA 2 [32], which has been employed for RAFT polymerizations of conventional conjugated monomers [53,58] as well as less active monomers [57]. The dithiocarbamate-type CTA 2 was also efficient for controlled alternating copolymerization of N-vinyl(na)phthalimide and N-isopropylacrylamide [50,56], in which intermolecular interactions via hydrogen bondings between two monomers determine the alternating tendency.…”

“…Controlled radical polymerizations of sulfur-containing vinyl monomers, such as pyridyl disulfide ethyl methacrylate [17][18][19][20], disulfide-based di(meth)acrylates [21][22][23][24], and vinyl monomers with protected thiol groups [25][26][27][28], have been employed in the production of a variety of functional polymers with well-defined structures and highly ordered architectures. Recently, we have also explored the controlled synthesis of sulfurcontaining polymers by reversible addition-fragmentation chain transfer (RAFT) polymerization of S-vinyl sulfonate esters [29,30] and S-vinyl sulfides [31][32][33], which belong to the family of S-vinyl monomers. Indeed, the RAFT polymerization of phenyl vinyl sulfide (PVS) and its derivatives has been successfully used to synthesize well-defined homopolymers and block copolymers with pendant thioether groups [31].…”

Rylene bisimide-based nanoparticles with cross-linked core and thermoresponsive shell using poly(vinyl amine)-based block copolymers

“…Recently, several approaches have been investigated to synthesize cross-linked coreeshell nanoparticles with characteristic optoelectronic properties by self-assembly of block copolymers and Suzuki-coupling reactions [40e43]. For example, we recently reported the synthesis of cross-linked coreeshell nanoparticles with p-conjugated components in the core via the self-assembly of block copolymers prepared by RAFT polymerization of 2,5-dibromo-3-vinylthiophene [40,41] and 4-bromophenyl vinyl sulfide [43]. In these systems, an in situ Suzuki coupling reaction was conducted between the cross-linkable (di)bromide groups in block copolymers and various diboronic acid compounds following the formation of micelles to afford stable cross-linked nanoparticles.…”