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The synthesis of poly­(thioether), a highly desired sulfur-containing polymer, is still a key challenge. Herein, we report a simple and facile approach to poly­(thioether)­s by closed-system one-pot reaction of carbonyl sulfide (COS) and epoxides. This route underwent the coupling reaction of COS with epoxides, followed by decarboxylative ring-opening polymerization (ROP) of the generated mixed cyclic thiocarbonates with releasing of CO2 and a little bit of COS. Organic base was used as catalyst and initiator in the two steps, respectively. The oxygen/sulfur exchange reaction was driven by successive regioselective elementary reactions and spontaneous releasing of CO2 (COS), leading to the sulfur atom of COS transferring to poly­(thioether)­s, which was well demonstrated by DFT studies. This work provides an easy-to-handle, metal-free route to poly­(thioether)­s bearing diverse structures by using readily available chemicals.

Lower disorder-to-order transition (LDOT) phase behavior is seldom observed in block copolymers (BCPs). Design of LDOT BCPs is important for broadening the applications and improving the high temperature properties of BCPs. In this work, the LDOT phase behavior was first achieved in the strongly interacting BCPs consisting of poly(ethylene oxide) (PEO) and poly(ionic liquid) (PIL) blocks (EO m -b-(IL-X) n , X: counterion) by introducing two extra strong forces (hydrogen-bonding and Coulombic interaction) with different temperature dependences. It is also found that the LDOT phase behavior of the EO m -b-(IL-X) n BCPs can be regulated by molecular weight (related to mixing entropy), counterion, and salt doping. Increasing counterion size and salt content shifts the disorder-to-order transition temperature (T DOT ) to higher temperature, whereas a higher molecular weight leads to a lower T DOT . Based on our findings, some general rules for design of LDOT phase behavior in the strongly interacting BCPs were proposed. Moreover, the conductivity of the EO m -b-(IL-X) n BCPs was correlated with the LDOT phase behavior. A remarkable increase in conductivity after LDOT, i.e., a thermo-activated transition, is observed for the EO m -b-(IL-X) n BCPs, which can be attributed to the cooperative effects of temperature rising and LDOT.

Ring-opening polymerization (ROP) of the bioderived and nonstrained γ-butyrolactone (γ-BL) is an emerging approach to produce recyclable polymers. It remains a big challenge to synthesize high molecular weight linear poly­(γ-butyrolactone)­s (PγBLs) in a highly active and selective manner. In this report, we developed dual organocatalysts for the ROP of γ-BL, using symmetrical (thio)­ureas with electron-donating groups to buffer the growing anions that were generared by the superbase phosphazene (P4). Linear PγBLs were selectively obtained with high apparent rate constant (ca. 39 times than single P4), and high number-average molecular weights of up to 64.3 kg/mol (ca. 3 times than single P4). The turnover frequencies of these P4/(thio)­urea pair-catalyzed processes were as high as 125 h–1. High molecular weight PγBLs exhibited dramatically improved mechanical properties.

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