On the influence of cylindrical sub-micrometer confinement on heptyloxycyanobiphenyl (7OCB). A dynamic dielectric study

Broadband dielectric spectroscopy (102 Hz to 1.8 × 109 Hz) was used to perform a study of the molecular dynamics of the liquid crystal heptyloxycyanobiphenyl (7OCB) in the bulk as well as confined to 0.2 μm diameter parallel cylindrical pores of Anopore® membranes in the isotropic and nematic phases. In bulk samples, two orientations (parallel and perpendicular) of the molecular director with regard to the probe electric field were investigated. In confined samples, untreated and HTBA-treated membranes were considered to obtain axial and radial confinements, respectively. The different molecular relaxation processes in bulk and confined samples were identified as well as discussed and compared.