posted on 2024-02-27, 13:03authored byKyoka Komaba, Hiroyuki Yoneyama, Hiromasa Goto
A polymerization
reaction in chiral liquid crystal produced electro-optically
active polymers from achiral furan–thiophene-based monomers.
The set of polymers prepared in this study had characteristics of
liquid crystal molecular order and organic semiconductors. The optically
active aromatic copolymers were synthesized via an electrochemical
method in cholesteric liquid crystals (Ch-LCs). Electrical properties
and chirality can be tuned to choose suitable monomer units. The polymers
obtained were evaluated by polarizing optical microscopy (POM), circular
dichroism, UV–vis spectroscopy, cyclic voltammetry, reflectance
spectroscopy, scanning electron microscopy, transmission electron
microscopy, and atomic force microscopy. POM observations of the products
showed a vortex-type fingerprint texture. Polymerization of the monomers
containing only two active polymerization sites produced the resultant
compounds with good transcription of the fingerprint texture and chirality
from the Ch-LC electrolyte solution. The membrane-forming behavior
can be improved by introducing furans at the edges of monomers. The
absorption bands derived from polarons and bipolarons as charge carriers
of conducting polymers can be tuned by an electrical redox process
and hydrazine vaporization treatment. Electrical control for the optical
activity of the furan–thiophene-based polymers was achieved.