DEsign oF hybrId Nanoparticles for Electrophoretic ink Display – DEFINED

The aim of this proposal is to rationally design non-aqueous pigmented polymeric dispersions with well-defined surface charge properties, controlled charge densities and good colloidal stability, for use as electrophoretic inks. Our strategy will build upon the synthesis of a library of polymeric dispersants with variable architectures and compositions incorporating ionic or ionizable functional groups with acidic or basic properties, to interact with inorganic pigments and provide surface charges. These polymers will be synthesized by reversible addition-fragmentation chain transfer (RAFT) radical polymerization and used to produce model colloidal suspensions in apolar media and encapsulate white and color pigment particles through RAFT-mediated dispersion polymerization. The synthesis of colored pigments with well-defined hues and optimized particle sizes is the second main objective of the DEFINED project. The developed strategy will not only help to alleviate the weaknesses of current multi-steps encapsulation processes, but will also allow a fine control of the pigment surface properties and inter-particle interactions through a deeper understanding of the charging mechanism in apolar media, which are essential prerequisite conditions for high-performance electrophoretic image displays (EPIDs). The gained knowledge on these original synthetic tools should ultimately result in the elaboration of two-color electrophoretic inks with high contrast, short response time and long-term stability.