Deep Holes in Free-Standing Smectic C Films

Abstract

Free-standing smectic films consist of smectic layers stacked in the film plane. In equilibrium, the discrete number of layers usually guarantees a uniform film thickness over large areas. Regions with differing numbers of layers are separated by dislocation lines. Their dynamics can be studied when the surface area is rapidly reduced, whereby excess material accumulates in islands (regions with increased thickness). Alternatively, holes (regions with reduced thickness) can be created by expanding the film surface, e. g. by means of a moveable film holder barrier. We study the growth of deep holes, i. e. regions which are up to several micrometers thinner than the surrounding film, using polarizing microscopy. The formation of regular dynamic stripe structures is observed.

Keywords:

• Smectic films
• dislocation dynamics
• pattern formation
• liquid crystals