This paper describes the synthesis of systematic sets of figure-eightand tadpole-shaped amphiphilic block copolyethers (BCPs) consisting of poly(decyl glycidyl ether) and poly[2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether], together with the corresponding cyclic counterparts, via combination of the t-Bu-P 4 -catalyzed ring-opening polymerization (ROP) and click cyclization. The clickable linear BCP precursors, with precisely controlled azido and ethynyl group placements as well as a fixed molecular weight and monomer composition (degree of polymerization for each block was adjusted to be around 50), were prepared by the t-Bu-P 4catalyzed ROP with the aid of functional initiators and terminators. The click cyclization of the precursors under highly diluted conditions produced a series of cyclic, figure-eight-, and tadpole-shaped BCPs with narrow molecular weight distributions of less than 1.06. Preliminary studies of the BCPs self-assembly in water revealed the significant variation in their cloud points depending on the BCP architecture, though there were small architectural effects on their critical micelle concentration and morphology of the aggregates.

This paper describes the comprehensive study of the lower critical solution temperature (LCST)-type thermoresponsive properties of various poly(glycidyl ether) homopolymers, varying in their side chain structure, molecular weight, and main chain tacticity, as well as their copolymers, varying in the monomer composition and monomer sequence. For the initial screening, we prepared nine kinds of poly(glycidyl ether)s by the phosphazene base-catalyzed ring-opening polymerization of glycidyl methyl ether (MeGE), ethyl glycidyl ether (EtGE), glycidyl isopropyl ether (iPrGE), 2-methoxyethyl glycidyl ether (MeEOGE), 2-ethoxyethyl glycidyl ether (EtEOGE), 2-propoxyethyl glycidyl ether (PrEOGE), 2-(2-methoxyethoxy)ethyl glycidyl ether (MeEO 2 GE), 2-(2-ethoxyethyl)ethyl glycidyl ether (EtEO 2 GE), and 2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether (MeEO 3 GE). Among them, poly(MeGE), poly(EtGE), poly(MeEOGE), poly(EtEOGE), and poly(MeEO 2 GE) (M n = ca. 5000 g mol -1 ) were found to exhibit the LCST-type phase transition in water at 65.5 °C, 10.3 °C, 91.6 °C, 41.3 °C, and 58.2 °C, respectively. Although the molecular weight and main chain tacticity had little impact on the phase transition temperature, the side chain structure, i.e., the number of oxythylene units and terminal alkyl group, significantly affected the transition temperature. The statistical copolymers composed of MeEOGE and EtEOGE revealed that the transition temperature of the polymer can be desirably customized in between those of the homopolymers by varying the monomer composition. On the other hand, we found that the block 3 copolymer composed of MeEOGE and EtEOGE exhibited a complex thermoresponsive behavior due to its ability to form a micellar aggregate. 4

A comprehensive set of amphiphilic star-shaped block copolyethers with a fixed molecular weight and composition was synthesized via the t-Bu-P 4 -catalyzed ringopening polymerization (ROP) of 2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether as a hydrophilic monomer and decyl glycidyl ether as a hydrophobic monomer. The threeand four-armed star-block copolyethers, i.e., the (AB) 3 -, (BA) 3 -, (AB) 4 -, and (BA) 4 -type star-block copolyethers, where A and B represent hydrophilic and hydrophobic blocks, respectively, were synthesized by the sequential t-Bu-P 4catalyzed block copolymerization using tri-and tetra-alcohol initiators, respectively, according to the core-first method. The homogeneous growth of each arm was confirmed by cleaving the linkages between the initiator residue and polyether arms. The synthesis of the A 2 B 2 -, AB 2 -, and A 2 B-type miktoarm star copolyethers was achieved by the combination of the t-Bu-P 4 -catalyzed ROP and azido-alkyne click chemistry. The azido-and ethynyl-functionalized precursor polyethers with the predicted molecular weights were separately prepared by the t-Bu-P 4 -catalyzed ROP with the aid of functional initiators as well as a terminator. The intermolecular click reaction of the precursors provided the desired miktoarm star copolyethers. All the obtained star-shaped block copolyethers had a comparable monomer composition (degree of polymerization = 50:50) and total molecular weight (ca. 22 200 g mol −1 ) with a narrow dispersity (<1.05). The hydrodynamic diameter and the cloud point analyses for the aqueous micellar solution of the amphiphilic star-shaped block copolyethers revealed that the self-assembly properties were affected by the block arrangements and branched architectures of the amphiphilic polymers.

This paper describes the systematic investigation into the aqueous self-assembly of a series of block copolymers (BCPs) consisting of maltoheptaose (MH; as the A block) and poly(ε-caprolactone) (PCL; as the B block), i.e., linear AB-type diblock copolymers with varied PCL molecular weights (MH-b-PCL (2.5k,3.3k,5k,10k) ), AB y -type (y = 2, MH-b-, which had been precisely synthesized via the combination of the living ringopening polymerization and click reaction. Under similar conditions, the nanoprecipitation method was employed to self-assemble them in an aqueous medium. Imaging and dynamic light scattering techniques indicated the successful formation of the carbohydrate-decorated nanoparticles via self-assembly. The MH-b-PCLs formed regular core−shell micellar nanoparticles with the hydrodynamic radius (R h ) of 17−43 nm. MH-b-(PCL 5k ) 2 and MH-b-(PCL 3.3k ) 3 , which have an N PCL comparable to MH-b-PCL 10k , were found to form large compound micelles with relatively large radii (R h of 49 and 56 nm, respectively). On the other hand, (MH) 2 -b-(PCL 5k ) 2 , (MH) 2 -b-PCL 10k , and (MH) 3 -b-PCL 10k predominantly formed the regular core−shell micellar nanoparticles (R h = 29−39 nm) with a size smaller than that of MH-b-PCL 10k (R h = 43 nm).

A series of brush block copolymers (BBCPs) consisting of poly(decyl glycidyl ether) (PDGE) and poly(10hydroxyldecyl glycidyl ether) (PHDGE) blocks, having four different types of chain tacticities, i.e., [atwhere the it and at represent the isotactic and atactic chains, respectively, were prepared by t-Bu-P 4 -catalyzed sequential anionic ring-opening polymerization of glycidyl ethers followed by side-chain modification. The corresponding homopolymers, i.e., at-PDGE, it-PDGE, at-PHDGE, and it-PHDGE, were also prepared for comparison with the BBCPs. The PDGE homopolymers were significantly promoted in the phase transitions and morphological structure formation by the isotacticity formation. In particular, it-PDGE was found to form only a horizontal multibilayer structure with a monoclinic lattice in thin films, which was driven by the bristles' self-assembling ability and enhanced by the isotacticity. However, the PHDGE homopolymers were found to reveal somewhat different behaviors in the phase transitions and morphological structure formation by the tacticity control due to the additional presence of a hydroxyl group in the bristle end as an H-bonding interaction site. The H-bonding interaction could be enhanced by the isotacticity formation. The it-PHDGE homopolymer formed only the horizontal multibilayer structure, which was different from the formation of a mixture of horizontal and tilted multibilayer structures in at-PHDGE. The structural characteristics were further significantly influenced by the diblock formation and the tacticity of the counterpart block. Because of the strong self-assembling characteristics of the individual block components, all the BBCPs formed separate crystals rather than cocrystals. The isotacticity always promoted the formation of better quality morphological structures in terms of their lateral ordering and orientation.

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