Facile synthesis of calabash-shaped and twin-tail tadpole-shaped copolymers via photothermal-induced topological transformation

Cascade synthesis of architecture-transformable thermo-labile multisite multiblock copolymers

“…Polymer Chemistry cene dimerization (Scheme S1 †), and the combination of thiolactone chemistry, [67][68][69][70][71] ring-opening polymerization (ROP), and UV-induced radical polymerization 72 and anthracene dimerization [19][20][21][22][23][24][25] is adopted to achieve (BAB) n -g-C/D-type multiblock graft copolymers, in which C is poly(ethylene glycol) (PEG), and D is poly(ε-caprolactone) (PCL) or poly(N-isopropylacrylamide) (PNIPAM). Meanwhile, thermolysis of (BAB) n -type copolymers is performed to obtain mixtures of P(St-co-MTL) l -b-PSt m (A′B) and P(St-co-MTL) l -b-PSt 2m -b-P(St-co-MTL) l (A′B 2 A′), and the thermolysis of PEG/PNIPAM-heterografted copolymer affords mixtures of comblike-linear and comblike-linear-comblike block copolymers.…”

“…Among them, architecture-transformable multisite polymers (ATMPs) are promising precursors to achieve a wide range of derivatives with distinct chain architectures. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] With the incorporation of stimu-lus-labile linkages into the backbone or end groups, ATMPs are subjected to reversible or irreversible topological transformations upon external stimuli. For instance, distinct functional linkers involving pH-cleavable ester group 18 and photo-/ thermo-labile anthracene dimer (AntD) group [19][20][21][22][23][24][25] have been incorporated into ATMPs to achieve stimulus-triggered cleavage and reconstruction of chain architectures.…”

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] With the incorporation of stimu-lus-labile linkages into the backbone or end groups, ATMPs are subjected to reversible or irreversible topological transformations upon external stimuli. For instance, distinct functional linkers involving pH-cleavable ester group 18 and photo-/ thermo-labile anthracene dimer (AntD) group [19][20][21][22][23][24][25] have been incorporated into ATMPs to achieve stimulus-triggered cleavage and reconstruction of chain architectures. The emergence of stimuli-responsive ATMPs allows to reconstruct novel architectural polymers via reaction driven topological transformation, during which the physical properties can be continuously regulated.…”

“…In this context, styrene (St) and 2-maleimidyl-4-thiobutyrolactone (MTL) are subjected to one-shot copolymerization to generate (BAB) n -type (A = P(St- co -MTL) 2 l , B = PSt m ) MMBPs via tandem ATRP and ATRC, followed by organobase-catalyzed cleavage of ester groups (OCE) to degrade into (A′B- co -BA′) r ′ -type copolymers with reduced block number and distinct connection mode of P(St- co -MTL) l (A′) and PSt m (B) blocks, in which l and m denote the degree of polymerization (Scheme 1). On this basis, representative MMBPs are chosen to synthesize intrachain folding MMBPs via UV-induced anthracene dimerization (Scheme S1†), and the combination of thiolactone chemistry, 67–71 ring-opening polymerization (ROP), and UV-induced radical polymerization 72 and anthracene dimerization 19–25 is adopted to achieve (BAB) n - g -C/D-type multiblock graft copolymers, in which C is poly(ethylene glycol) (PEG), and D is poly( ε -caprolactone) (PCL) or poly( N -isopropylacrylamide) (PNIPAM). Meanwhile, thermolysis of (BAB) n -type copolymers is performed to obtain mixtures of P(St- co -MTL) l - b -PSt m (A′B) and P(St- co -MTL) l - b -PSt 2 m - b -P(St- co -MTL) l (A′B 2 A′), and the thermolysis of PEG/PNIPAM-heterografted copolymer affords mixtures of comblike-linear and comblike-linear-comblike block copolymers.…”

Polyacetylene‐Based Asymmetric Bicyclic Polymer by Blocking‐Cyclization Technique

“…However, it was worth noting that most of the reported polymers are symmetrical bicyclic polymers, where the size of each ring was the same. With further research, studies on asymmetric bicyclic polymers were now being reported, [29][30][31][32] for example, Tezuka et al [31] synthesized block copolymers consisting of topological amphiphilic segment pairs through the process of "electrostatic self-assembly and covalent fixation" process, which including an "8" shape as well as a four-armed star shape, along with two asymmetric topological forms, that is, twin-tailed tadpole shapes. Recently, Zhao [32] crafted innovative copolymers in the form of calabashshaped and tadpole-shaped structures, consisting of PS and PCL segments, in order to elucidate the impact of topology.…”