  Droplets confined in a microfluidic channel often exhibit intriguing shapes,
primarily attributable to complex hydrodynamic interactions over small scales.
We show that effect of varied substrate wettability conditions may further
complicate these interactions remarkably, and often non-trivially. Our studies
reveal that the combined influence of substrate wettability and fluidic
confinement eventually culminates towards influencing the droplet transients,
distortion of the local shear flow field, as well as drop stabilization against
breakup or detachment, allowing one to develop different regimes of shapes
evolution that are fascinatingly distinct from the ones reported in earlier
studies on drop breakup in micro-confined shear flows. We further demonstrate
that combined consequences of wall effects and interfacial wettability
characteristics can be exploited to pattern microfluidic substrates with
pre-designed patches, bearing far-ranging scientific and technological
consequences in several scientific and technological applications of
contemporary relevance.
