  The contact line dynamics of a thermal field assisted flow configuration of
two immiscible fluids is considered in a narrow thermofluidic pathway. The
surfaces of the channel are wetted with predesigned wettabilities and
interdigitated electrodes are mounted on the substrates to generate non-uniform
electric field. In this study, the interplay of thermocapillary and
electrothermal forces on interfacial dynamics are studied in detail. The former
is caused by surface tension gradients while the latter results from gradients
in permittivity and electrical conductivity. Our investigations reveal that the
relative strength of interfacial forces and electrothermal forces and their
interactions can be effectively used to control the capillary filling time as
well as the flow dynamics. For same strength of thermocapillary and
electrothermal forces (characterized by individual dimensionless numbers)
electrothermal forces dominate over thermocapillary forces. However,
interfacial forces at some wettabilities dominate over electrothermal forces
and set the fluid motion toward the entry of the channel.
