Tridodecylamine, an efficient charge control agent in non-polar media for electrophoretic inks application
Résumé
In order to obtain efficient electrophoretic inks, Tridodecylamine (Dod3N), has been studied as charge control
agent (CCA) in a non-polar paraffin solvent (Isopar G) for various inorganic pigments (TiO2 and Fe2O3).
All hydrophobic mineral oxides, i.e. treated with octyltrimethoxysilane (C8) or dodecyltrimethoxysilane
(C12), were found to be negatively charged in presence of Dod3N. The electrophoretic mobilities of
inorganic pigments seemed to be strongly dependent of their isoelectric point (IEP) and also of the concentration
of dod3N with an optimum range between 10 and 20 mM depending on the pigments. Finally,
an electrophoretic ink constituted of hydrophobic mineral oxides in presence of Dod3N was tested in a
device. Its efficiency as charge control agent to negatively charge hydrophobic particles was confirmed
through good optical properties and fast response time (220 ms at 200 kV m−1).