posted on 2021-07-14, 14:39authored byYoung-Jae Jin, Hyojin Kim, Jineun Lee, Heesang Kim, Toshiki Aoki, Giseop Kwak
Noncovalent
chemistry may offer diversity in the functions and
applications for artificial polymers by allowing various ordered–disordered
phase transitions in a precisely controlled manner. To verify this
notion from a fundamental perspective, we examined an achiral poly(phenylacetylene)
derivative with an α-helical structure as a helical-spring polymer
for revealing phase changes through control of intramolecular hydrogen
bonding with the chiral solvent and temperature. When an amine capable
of hydrogen bonding was used as the chiral solvent, either an irreversible
helix–helix or a reversible helix–coil phase change
occurred in an optically dissymmetric manner according to the amount
of the chiral solvent added and ambient temperature. Considering the
hydrogen-bonding strength values of the solvent mixture and the thermodynamic
parameters, we could predict if the optical-dissymmetry phase changes
would occur and, if so, how they occur. Our results were similar to
those see for the denaturation of proteins, induced by solvent and
temperature, based on helix–coil phase transition.