Formation of irreversible nearly transparent physical polymeric hydrogels during a modified microemulsion polymerization

A modified microemulsion polymerization procedure has been successfully employed to prepare high solids-content nanosized polymeric microemulsions, in which the monomer was gradually added into the polymerizing microemulsion without disturbing its stability. When the system was emulsified by anionic surfactant and initiated by redox initiators at ambient temperature, a high polymer/surfactant ratio (7:1 or higher) and relatively concentrated polymeric microemulsions (10-40 wt% polymer) were achieved while maintaining the particle diameters smaller than 20 nm. The formation of transparent polymeric hydrogels during this process is discussed.