Abstract
Using a photo-responsive dimer exhibiting the transition between nematic (N) and twist-bend nematic (NTB) phases, we prepared spherical cap-shaped droplets on solid substrates exposed to air. The internal director structures of these droplets vary depending on the phase and on the imposed boundary conditions. The structural switching between the N and NTB phases was successfully performed either by temperature control or by UV light-irradiation. The N phase is characterized by an extremely small bend elastic constant K3, and surprisingly, we found that the droplet-air interface induces a planar alignment, in contrast to that seen for typical calamitic liquid crystals. As a consequence, the director configuration was stabilized in a structure substantially different from that normally found in conventional nematic liquid crystalline droplets. In the twist-bend nematic droplets characteristic structures with macroscopic length scales were formed, and they were well controlled by the droplet size. These results indicated that a continuum theory is effective in describing the stabilization mechanism of the macroscopic structure even in the twist-bend nematic liquid crystal droplets exhibiting director modulations on a scale of several molecular lengths.
Original language | English |
---|---|
Pages (from-to) | 989-998 |
Number of pages | 10 |
Journal | Soft matter |
Volume | 15 |
Issue number | 5 |
Early online date | 8 Jan 2019 |
DOIs | |
Publication status | Published - 7 Feb 2019 |
Bibliographical note
The stays and research activities of J. Y. and F. A. in Hungary, and P. S. and A. B. in Japan are supported by the JSPS-HAS bilateral program. J. Y. was partially supported by JSPS KAKENHI Grant Number 15K17739. A. J. acknowledges financial support byNSF DMR: 1307674. Financial support from the grants NKFIH PD 121019 and FK 125134 are acknowledged.