A two-phase electrophoretic medium comprises a continuous phase and a
discontinuous phase. The discontinuous phase comprises a plurality of
droplets, each of which comprises a suspending fluid and at least one
particle disposed within the suspending fluid and capable of moving
through the fluid upon application of an electric field to the
electrophoretic medium. The continuous phase surrounds and encapsulates
the discontinuous phase. To reduce the humidity sensitivity of the
medium, a non-ionizable or crystalline polymer may be used as the
continuous phase.