Liquid toners for Electrophotographic applications are colloidal dispersions of charged particles (0.1-0.5μ) colored by a dye or pigment in a solvent of very low dielectric constant. The stability of particle systems in such solvents is effected by soluble polymers with a positive charge either by adsorption or chemical interaction. For hydrocarbon solvents such as Isopar™ (δ∼7.2), polymers and copolymers largely comprising lauryl methacrylate (LMA) and isobornyl acrylate (IBOA) with solubility parameters (δ) of 7.9 and 7.8 respectively serve as polymeric dispersants for organic pigments. Macromers of such polymers can stabilize organosols produced by dispersion polymerization. For perfluorinated solvents (Fluorinert™), perfluoroacrylate polymers or macromers serve as dispersants for all types of particles. Fine particles of perfluorinated polymers can also be generated by significantly modifying the Flory-Huggins polymer-Fluorinert™ interaction parameter χ of the said polymers to ≫0.5 by insertion in the main chain or pendant position segments that are thermodynamically immiscible resulting in the collapse of the chain. Incorporation of siloxane or perfluoroalkyl units in polyacrylate dispersants facilitate the release of toner films from photoconductor surface in electrophotography.
S.P. Rao, C.J. Hitzman, S.V. Pathre, "Designing of Liquid Toner Materials in Hydrocarbon and Perfluorinated Solvents" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP16), 2000, pp 242 - 245, https://doi.org/10.2352/ISSN.2169-4451.2000.16.1.art00065_1