Hard versus soft confinement effects on molecular dynamics of 4-hexyl-4′-isothiocyanatobiphenyl liquid crystals

The purpose of this work is to exam the dynamic properties of 4-hexyl-4′-isothiocyanatobiphenyl (6BT) experiencing different forms of confinement. Hard confinement was achieved by the infiltration of LCs into nanoporous aluminium oxide (AAO) templates with non-intersecting, cylindrical, channels. Soft confinement derived from the interactions between polymer and guest liquid crystalline molecules was investigated on an example of electrospun polymer/liquid crystal composite fibres. We prepared composite fibres for three different mass ratios of polycaprolactone (PCL) and 6BT. The formation of liquid crystalline domains in fibres was confirmed by polarizing microscope observations and their distribution was illustrated by Raman. The intra-molecular interactions in composite fibres were revealed by analysis of the temperature dependencies of specific infrared (IR) absorption bands. By a combination of broadband dielectric spectroscopy with the other spectroscopic methods, the microscopic picture of role of soft and hard confinement on molecular dynamics and a crystallization process in liquid crystals is obtained.