Phase transitions in nanocomposites of hydrogen-bonded dimeric liquid crystals with mesogenic and non-mesogenic components

Abstract

Microtextural polarization, phase transitions, and electro-optical effects are studied in a series of nanocomposites, grown by mixing alkyloxybenzoic acids (nOBAs), displaying hydrogen-bonded dimeric liquid crystal (LC) state, with non-mesogens (single-walled carbon nanotubes (SWCNTs), perfluorooctanoic acid) or mesogens (bent-core LC compound D14F3). Each of the studied nanocomposites, in which the nOBA serves as a matrix, forms complexes with bent-shaped dimeric, caused by the interaction between the dopant structural units and the dimer rings. This feature, coordinated with the surface anchoring, bulk and electrical effects, leads to drastic reduction of the LC system symmetry. As a result, transitions from achiral (characteristic for the pristine nOBA) to chiral states (including ferroelectric smectic C with C₂ symmetry and ferroelectric smectic C_G with the lowest C₁ triclinic one) take place. The functionalization of the SWCNTs causes drastic increase of the ferroelectricity.

Keywords:

• dimer liquid crystals
• nanotube functionalization
• chirality
• ferroelectricity
• electrical polarization

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work is supported by the Bulgarian National Funds for Scientific Research [grant number DFNI-G02/18].