Multi-Functional Hyperbranched Poly(vinylene sulfide)s Constructed via Spontaneous Thiol–Yne Click Polymerization

Multifunctional hyperbranched polymers have found wide applications in diverse areas. However, the preparation of these polymers is generally under harsh polymerization conditions with limited reactions. In this work, we prepared multifunctional hyperbranched poly­(vinylene sulfide)­s (<i>hb</i>-PVSs) by our established efficient and spontaneous thiol–yne click polymerization for the first time. A series of <i>hb</i>-PVSs with high molecular weights (<i>M</i>_w up to 63100) were obtained in high yields (up to 86%) from the polymerizations of monomers <b>1</b> and <b>2</b> with equivalent molar ratio in THF at 20 °C for 2 h. All the <i>hb</i>-PVSs are regioregular, soluble, and thermally stable. Thanks to the unreacted ethynyl groups on their peripheries, the <i>hb</i>-PVSs could be facilely functionalized by consecutive thiol–yne click reactions. Moreover, the solid films of <i>hb</i>-PVSs exhibit higher refractive index (RI) values (<i>n</i> > 1.64) than those of traditional optical plastics. The TPE-containing <i>hb</i>-PVS shows unique aggregation-enhanced emission characteristic and its aggregates could be used to detect explosives with superamplification effect. Therefore, this work not only proves the universality of our developed spontaneous thiol–yne click polymerization but also provides a powerful and versatile platform for the preparation of multifunctional sulfur-containing polymers

Catalyst-Free Thiol–Yne Click Polymerization: A Powerful and Facile Tool for Preparation of Functional Poly(vinylene sulfide)s

The “thio-click” polymerization is a well-expanded concept of click polymerization. Among the click polymerizations, the thiol–yne click polymerization is less developed and still in its infancy stage. In general, UV light, elevated temperature, amine, or transition metal complexes is needed to catalyze the thiol–yne click polymerization, which greatly complicates the experimental operation and limits its application. In this work, a facile and powerful thiol–yne click polymerization was developed, which could be carried out under very mild conditions without using external catalyst. Simply mixing the aromatic diynes (<b>1a</b>–<b>1e</b>) and dithiols (<b>2</b>–<b>4</b>) with equivalent molar ratio in THF at 30 °C will readily produce soluble and regioregular functional poly­(vinylene sulfide)­s (P<b>Ia</b>–P<b>Ie</b>, P<b>II</b>, and P<b>III</b>) with high molecular weights (<i>M</i>_w up to 85 200) in excellent yields (up to 97%) after as short as 2 h. Furthermore, no double addition product of an ethynyl group was found. This catalyst-free thiol–yne click polymerization has remarkably simplified the reaction conditions and will facilitate the preparation of functional materials applied in diverse areas