Self-assembly behavior of amphiphilic C₆₀-end-capped poly(vinyl ether)s in water and dissociation of the aggregates by the complexing of the C₆₀ moieties with externally added γ-cyclodextrins

Controlled Synthesis and Photoresponsive Properties of Spiropyran End-Functionalized Poly(vinyl ether)s

Due to the need to develop smart materials for a variety of applications such as catalysts and drug delivery, the development of photoresponsive polymers is receiving increasing attention. In particular, the photoisomerization of spiropyran (SP), unlike many other photoresponsive compounds, has attracted attention because it dramatically changes not only the molecular structure but also the polarity of the molecule. However, in most cases where SP is used as a photoresponsive functional group, SP is introduced in the side chain of the polymer, and few cases have been reported in which SP is introduced at the end of the polymer chain. Therefore, we designed a new amphipathic poly(vinyl ether) with an SP moiety at the end of the polymer chain. First, an initiator having an SP moiety was synthesized and used for living cationic polymerization to synthesize a poly(vinyl ether) bearing an SP moiety at the end of the polymer chain. Furthermore, we investigated the photoresponsive properties of the obtained polymers, we found that self-assembly of the amphiphilic polymers could be controlled by photoirradiation.

Recent Advances in Living Cationic Polymerization with Emerging Initiation/Controlling Systems

While the conventional living cationic polymerization (LCP) provided opportunities to synthesizing well-defined polymers with predetermined molecular weights, desirable chemical structures and narrow dispersity, it is still important to continuously innovate new synthetic methods to meet the increasing requirements in advanced material engineering. Consequently, a variety of novel initiation/controlling systems have be demonstrated recently, which have enabled LCP with spatiotemporal control, broadened scopes of monomers and terminals, more user-friendly operations and reaction conditions, as well as improved thermomechanical properties for obtained polymers. In this work, recent advances in LCP is summarized with emerging initiation/controlling systems, including chemical-initiated/controlled cationic reversible addition-fragmentation chain transfer (RAFT) polymerization, photoinitiated/controlled LCP, electrochemical-controlled LCP, thionyl/selenium halide-initiated LCP, organic acid-assisted LCP, and stereoselective LCP. It is hoped that this summary will provide useful knowledge to people in related fields and stimulate new ideas to promote the development and application of LCP in both academia and industry.

Controlled Synthesis of Poly(vinyl ether)-Grafted Poly(phenylacetylene)s by a Combination of Living Coordination Polymerization and Living Cationic Polymerization

We newly designed a functionalized monomer (PhAVE-AcOH) containing a phenylacetylene (PhA) group and a 1-(acetoxy)ethoxy group, the latter of which is expected to act as an initiator moiety in combination with Lewis acid-based activators under living cationic polymerization conditions. A polyPhA-based multifunctional initiator poly(PhAVE-AcOH) with a narrow molecular weight distribution (M _w/M _n = 1.02) was synthesized by Rh complex-mediated living coordination polymerization of PhAVE-AcOH. Then, living cationic graft polymerization of isobutyl vinyl ether (IBVE) was performed employing the pendant 1-(acetoxy) ethoxy initiating moiety of poly(PhAVE-AcOH) to form polyIBVE-grafted polyPhA(polyPhA-g-polyIBVE), where both the main chain and side chains possessed well-controlled structures (M _w/M _n = 1.05-1.10). We found that UV-vis absorption spectra of polyPhA-g-polyIBVE were progressively redshifted with increasing molecular weights of the graft chain.

Precise synthesis of double-armed polymers with fullerene C60 at the junction for controlled architecture

We report the first successful synthesis of the polymer-attached 1,2-hydrofullerene and the double-armed 1,4-bisadducts in a regioselective manner via controlled radical reactions.