We present analytical, numerical and experimental
studies of capillary ridges, that is, of long, narrow strips
of liquid partially wetting a flat or curved substrate.
Such thin film geometries possess both free
boundaries and moving contact lines, and are
known to display a large variety of instability phenomena.
They provide an excellent example of the mechanism of dewetting
due to capillary instability.
Here, the possibility of dewetting and subsequent breaking of the continuous
liquid strip into a sequence of droplets is essentially the result
of flow induced by an excess of interfacial energies of the liquid/vapor,
liquid/solid, and solid/vapor interfaces.
We address two fundamental questions: (i) under what geometric and material
conditions such solid/liquid configurations remain absolutely stable, and (ii)
how the degree of contact line slip
affects the liquid ridge morphological changes,
dewetting growth rate, most unstable wavelength of instability,
and long-term breakup times.