Spontaneous mirror symmetry breaking and chiral segregation in the achiral ferronematic compound DIO

DOI: 10.1039/D3CP00357D

Authors: Neelam Yadav (rinity College Dublin, The University of Dublin) , Yuri P. Panarin (TU Dublin) , Wanhe Jiang (University of Hull) , Georg Mehl (University of Hull) , Jagdish K. Vij (Trinity College Dublin, The University of Dublin)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Chemistry Chemical Physics , VOL 30

State: Published (Approved)
Published: March 2023
Diamond Proposal Number(s): 30755 , 31552

Abstract: An achiral compound, DIO, known to exhibit three nematic phases namely N, NX and NF, is studied by polarizing microscopy and electro-optics for different surface conditions in confinement. The high temperature N phase assigned initially as a conventional nematic phase, shows two additional unusual features: the optical activity and the linear electro-optic response related to the polar nature of this phase. An appearance of chiral domains is explained by the spontaneous symmetry breaking arising from the saddle-splay elasticity and followed by the formation of helical domains of the opposite chirality. This is the first example of helical segregation observed in calamitic non-chiral molecules in the nematic phase. As reported previously, the ferronematic NF shows strong polar azimuthal surface interaction energy which stabilizes a homogeneous structure in planar aligned LC cells rubbed parallel and exhibits a twisted structure in cells with antiparallel buffing. The transmission spectra are simulated using Berreman's 4 × 4 matrix method. The observed agreement between the experimental and the simulated spectra quantitatively confirms the presence of twisted structures in antiparallel rubbed cells.

Subject Areas: Chemistry


Instruments: B23-Circular Dichroism

Added On: 28/03/2023 17:25

Documents:
d3cp00357d-2.pdf

Discipline Tags:

Physical Chemistry Chemistry

Technical Tags:

Spectroscopy Circular Dichroism (CD)