Versatile preparation of surface-skinless particles of epoxy resin-based monoliths using a well-defined diblock copolymer surfactant

Epoxy resin-based monoliths, possessing a bicontinuous structure that consists of a porous channel and a resin skeleton, have a broad range of applications such as chromatography; however, the preparation of spherical particles has been limited so far. This is the first report on a versatile and facile preparation method for surface-skinless monolithic particles with micrometer diameters by polymerization-induced phase separation in an oil-in-oil emulsion system. The key to success is the addition of a well-defined block copolymer surfactant, compatible for both the dispersed and continuous phases in suspension polymerization. In essence, the volume ratio and length of the block copolymers are crucial to control the stability of the emulsion and the suppression of the unwanted skin layer on the surface of the produced particles. The present work represents a new direction for versatile and large-scale preparation of monolithic particles, including silicates and polyacrylates, with several surface properties.