Smectic Order in a Porous Interconnected Substrate

Measurement of the specific heat and small angle neutron scattering studies for nCB liquid crystals confined to the 0.05 μm diameter pores of Millipore filters, a fibrous porous substrate, reveal that in spite of the interconnection and restrictive size, smectic layers are formed. The existence of this long range smectic order that increases with decreasing temperature is in contrast to findings in other porous geometries where a smectic phase is either absent or greatly suppressed by the confinement. For 9CB, we also study the possible effects of confinement on the critical behavior at the second order smectic-A to nematic phase transition.