Cover Image, Volume 51, Issue 19



The image represents the formation of polystyrene particles by an uncommon heterocoagulation mechanism, by which small precursor particles, continuously formed throughout the surfactant-free emulsion polymerization, are captured on the surface of large mature particles, contributing to their growth. The resulting spherical particles exhibit a peculiar surface roughness. This mechanism is investigated on page 3997 by Andrew M. Telford, Binh T. T. Pham, Chiara Neto, and Brian S. Hawkett as part of work on a novel, robust approach to produce micrometer-sized polystyrene particles with narrow size distribution in the presence of air. The approach could be easily employed by those not skilled in the art, to produce large quantities of polymer particles for research applications in a simple way.