The process of surface modification of hydrophobic organic pigments (copper phthalocyanine (CuPc) and carbon black) as well as a hydrophilic inorganic pigment (titanium dioxide) in aqueous dispersions by employing tailor-made thermo-responsive copolymers, and the colloidal stability have been studied. The pigment surface modification is achieved by conventional adsorption and by (thermo)precipitation of amphiphilic methyl vinyl ether (MVE) containing polyvinylether block and PMVE graft copolymers with poly(ethylene oxide) side chains exhibiting a lower critical solution temperature (LCST). The effect of mechanical treatment of the pigment dispersion by ultrasonic power alone or in combination with the LCST property was investigated. The course of the pigment surface coating process was followed by the Electrokinetic Sonic Amplitude (ESA) method. The temperature-controlled sorption of PMVE-g-PEO graft copolymers on both inorganic and organic pigment surface was investigated. It was found that ultrasonic treatment together with LCST thermoprecipitation is a promising method for the surface modification of pigments with regard to dispersion stability.
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