Synthesis and characterisation of urea–formaldehyde microcapsules containing electrophoretic fluid with red–white particles

Abstract

A series of functional microcapsules were prepared via in situ polymerisation technology with poly(urea–formaldehyde) resin as wall material and electrophoretic fluid containing red–white particles as core materials. The urea–formaldehyde microcapsules were characterised by optical microscopy, scanning electron microscopy and particle size analysis. It was found that sodium dodecyl sulphate (SDS) plays an important role in the formation of the microcapsule wall, and the concentration of SDS mainly affects the yield and surface feature of the microcapsules. The microcapsules prepared with SDS concentration of 2·5×10−3 mM at a dispersing stirring rate of 600 rev min−1 demonstrated good surface topography and suitable sizes. These microcapsules were applied successfully to prepare a clock display operated at a direct current voltage of 20 V, demonstrating that these microcapsules are potential candidates for applications in the area of electrophoretic displays.