Observation of macro-heterogeneities in surface-stabilized smectic C* with antagonistically patterned substrates

Abstract

East Economic-Legal Humanitarian Academy, Mendeleeva st., 215 / 4, Ufa, 450071, RussiaIn our recent study, we considered equilibrium states in a monolayered sample of ferroelectric liquid crystal in smectic C* phase confined between two differently patterned substrates with strong anchoring under the applied electric field. By using the continuum theory for a "bookshelf " aligned sample for smectic C*, we derived an elliptic sine-Gordon equation. It was shown that due to the antagonistic boundary conditions at the substrates, competing boundary effects in the thin film generate a stable alignment of the smectic C* director. This alignment can be controlled by the electric field. The result obtained was explained basing on Frenkel-Kontorova's model, which was used to describe the map of the director alignment as the system of harmonically coupled "atoms" with the external potential produced by the substrates. In this study, we perform an experiment to verify our theoretical results. We prepared a cell with differently patterned substrates, and ferroelectric liquid crystal material CS-1024 (Chisso Co.) was injected into the empty cell by the capillarity flow. Patterned monolayers promoting planar alignment of CS-1024 in its smectic C* phase were created using microcontact printing of functionalized organothiols on gold films. By patterning the surface with planar alignment of monolayers, the location and formation of smectic C* director macro-heterogeneities can be controlled by the electric field. The observed macro-heterogeneities continue to exist when the electric field is turned off. Polarizing microscopy and fluorescent microscopy were used to observe the formation of macro-heterogeneities in the alignment of SmC* director field.