Electrophoretic ink displays are a technology offering the quality of printed paper and very low
power consumption. They contain electrically charged black and white pigment particles in a
nonpolar liquid such as oil, that can be moved around by applying appropriate voltages. This way,
every pixel of the display can be made either black or white. For low energy consumption the
particles need to stay at the surface when no voltage is applied, so power is only needed to change
the image. The interactions between particles and surfaces are not sufficiently understood to
efficiently design bistable electrophoretic displays. Improved models are also needed for next
generation electrophoretic devices with video-speed switching, where particle movements occur
in a small layer close to the surface. Also for industrial printing, where very similar principles are
used to deposit ink on a paper surface, particle-surface interactions are important. The goal of this
project is to investigate particle-surface interactions in nonpolar liquids, by combining single and
multiple particle measurements with nanometer accuracy close to the surface. The experiments
are based on light that totally reflects at the surface, and is dependent on the presence of particles
near that surface. These experiments will yield a better understanding of the particle-surface
interactions and allow to predict particle behavior in order to improve applications such as E-ink
displays and liquid toner printing.