An electrophoretic particle salt that includes a cationic electrophoretic particle and an anionic group ionically associated with the cationic electrophoretic particle is employed in an electrophoretic display. A spacer group chemically bonds a cationic moiety to a surface of the electrophoretic particle. A method of making the electrophoretic particle salt includes particle surface modification, nucleophilic substitution to create an interim salt and anion exchange. The electrophoretic particle salt has an ionization constant that favors dissociation into a positively charged electrophoretic particle and the anionic group in a nonpolar medium. The electrophoretic display includes a pair of electrodes and a dispersion of the electrophoretic particle salt in a nonpolar medium in a gap between the pair of electrodes.