Twist-bend nematic phases of bent-shaped biaxial molecules.
How can a change in molecular structure affect the relative stability and structural properties of the twist-bend nematic phase (NTB)? Here we extend the mean-field model(1) (C. Greco, G. R. Luckhurst and A. Ferrarini, Soft Matter, 2014, 10, 9318) for bent-shaped achiral molecules, to study the influence of arm molecular biaxiality and the value of the molecule's bend angle on the relative stability of NTB. In particular we show that by controlling the biaxiality of the molecule's arms, up to four ordered phases can become stable. They involve local uniaxial and biaxial variants of NTB, together with uniaxial and biaxial nematic phases. However, a V-shaped molecule shows a stronger ability to form stable NTB than a biaxial nematic phase, where the latter phase appears in the phase diagram only for bend angles greater than 140° and for large biaxiality of the two arms.
Marian Smoluchowski Institute of Physics, Department of Statistical Physics, Jagiellonian University, prof. S. Łojasiewicza 11, 30-348 Kraków, Poland. wojciech.tomczyk@doctoral.uj.edu.pl grzegorz@th.if.uj.edu.pl lech.longa@uj.edu.pl.
Wojciech
W
Tomczyk
Grzegorz
G
Pająk
Lech
L
Longa