  We use experiments to study the dynamics of the healing of a blister, a
localized bump in a thin elastic layer that is adhered to a soft substrate
everywhere except at the bump. We create a blister by gently placing a glass
cover slip on a PDMS substrate. The pressure jump across the elastic layer
drives fluid flow through micro-channels that form at the interface between the
layer and the substrate; these channels coalesce at discrete locations as the
blister heals and eventually disappear at a lower critical radius. The spacing
of the channel follows a simple scaling law that can be theoretically
justified, and the kinetics of healing is rate limited by fluid flow, but with
a non-trivial dependence on the substrate thickness that likely arises due to
channelization. Our study is relevant to a variety of soft adhesion scenarios.
