Self-Assembly and Molecular Electrical Switching Property of Phthalocyanine-Based Liquid-Crystalline Poly(Styrene Sulfonic Acid) Compounds

A series of phthalocyanine-based liquid-crystalline poly(styrene sulfonic acid) compounds (LCPCs) are synthesized using cholesterol, dicarboxylic acid, amino- zinc phthalocyanine, and polystyrene sulfonic acid. The chemical structure, thermal property, liquid-crystalline behavior, direct current conductivity, and temperature-controlled molecular electronic switch property are investigated by use of various techniques. The LCPCs show both columnar phase (Col(h)) induced by the phthalocyanine moieties and nematic discotic (N-d) phase formed by the collapse of the columnar phase structure. The temperature-dependent conductivity of the LCPCs is associated with the activation energy evaluated by Broido's graphical procedure according to the thermogravimetric analytical curves. The LCPCs show low conductivity derived from 1D charge migration through phthalocyanine cores in the col(h) phase, but exhibit high conductivity due to 3D ionic charge transport in the N-d phase. A temperature-controlled molecular electronic switch is fabricated on the basis of the temperature-dependent conductivity property, which can be useful for some potential applications.

Automated summary

A series of phthalocyanine-based liquid-crystalline poly(styrene sulfonic acid) compounds were synthesized and investigated for their chemical structure, thermal property, liquid-crystalline behavior, and electrical conductivity properties. The compounds exhibited temperature-dependent conductivity with different charge transport mechanisms leading to low and high conductivity behaviors. Additionally, a temperature-controlled molecular electronic switch was fabricated based on the temperature-dependent conductivity property for potential applications.