Spontaneous Room-Temperature Polymerization of Carbon Disulfide in Water Microdroplets

Water microdroplets have emerged as extraordinary reaction vessels in which ultrahigh electric fields at the air–water interface generate reactive radicals and hydrated electrons, enabling transformations inaccessible in bulk solution. However, microdroplet-induced free-radical polymerization has remained virtually unexplored. Here we demonstrate that aqueous microdroplets induce the rapid, room-temperature polymerization of carbon disulfide (CS 2 ) into a poly(carbon sulfide) solid. The reaction consumes CS 2 completely without catalysts at room temperature. Comprehensive characterization reveals a highly cross-linked polymer composed of conjugated C═C and C–S networks with incorporated hydrogen. Radical quenching and online mass spectrometry experiments reveal a mechanism involving electron transfer at the droplet interface, initiating stepwise CS 2 radical polymerization pathway. Gram-scale preparation is readily achieved through through small-scale parallel reactions. This discovery establishes first microdroplet-mediated polymerization for polymer synthesis and offers a viable strategy for CS 2 pollutant valorization.