Capsules, materials for use therein and electrophoretic media and displays containing such capsules

A process for forming a capsule, the process comprising:

• providing a liquid internal phase comprising a fluid and a first prepolymer dispersed therein and having a plurality of first reactive groups;
• providing a dispersion medium substantially immiscible with the internal phase and comprising a dispersing liquid and a second prepolymer dispersed therein and having a plurality of second reactive groups, each of the second reactive groups being capable of reacting with at least one of the first reactive groups;
• and
• dispersing the internal phase as a plurality of discrete droplets in the dispersion medium, thereby causing the first and second reactive groups to react together to form a polymer shell surrounding the droplets, and thereby forming capsules comprising the fluid.