The influence of an external electric field (applied to the nematic liquid crystal layer) on the morphology of the nematic-liquid-crystal–air interface has been studied experimentally in radial Hele-Shaw geometry. The effective viscosity ${\mu }_{\mathrm{eff}}$ of the nematic has been tuned by the electric field E and by the flow. At low excess pressure $p_e$ (where the growth of the interface is controlled mainly by the surface tension $\sigma ),$ the applied E has no significant influence on the morphology of the interface, but decreases its normal velocity due to the increase of ${\mu }_{\mathrm{eff}}.$ At higher $p_e$ (where the growth is not only controlled by $\sigma ,$ but also by the kinetic term that depends on the effective viscosity) a significant difference in the morphology has been observed as a function of E. Experiments have shown that the influence of the electric field on the pattern morphology increases with the driving force (pressure gradient).

• Received 30 May 2002

DOI:https://doi.org/10.1103/PhysRevE.67.041717