Highly Stable Microcapsules of Colloidal Photonic Ink in Nonpolar Medium for Full Color E‐Skin Device

The colloidal dispersion in a nonpolar medium is an essential material for electrophoretic displays (EPD) with low-power consumption. A uniform-sized superparamagnetic iron oxide nanoparticle (SPION) promising candidate EPD, which exhibits tunable structural color by Bragg diffraction. In this study, the surface of SPION charged inverse micelles Solsperse-17k, oil-soluble polymeric surfactant. photonic ink simultaneous magnetochromism and electrochromism. encapsulated via complex coacervation process, double layers gelatin/gum Arabic form stable shell µ-capsule. µ-capsules show colors, depends upon size ink. increased surfactant content brings about decrease µ-capsule due to reduced tension. lowered gelatin concentration during results smaller µ-capsule, electrical tunability. Optical characterization using confocal microscopy enables 3D visualization inner structure formation particle chain H-field. 1 year, illuminating long-term stability developed study.