Dr. Jun-Ichi Fukuda - A zigzag defect structure in a nematic liquid crystal and its utility as a chirality sensor

Datum objave: 14. 10. 2014
Seminar fizike mehkih snovi
Sreda, 15.10.2014, ob 15:15 v seminarski sobi fizike, IJS - glavna stavba (soba 106).

A zigzag defect structure in a nematic liquid crystal and its utility as a chirality sensor

Dr. Jun-ichi Fukuda, Nanosystem Research Institute (NRI), AIST, Tsukuba, Japan

I show that, when confined in a microwrinkle groove, a nematic liquid crystal accommodates a topological line defect (disclination) of zigzag form [1]. The formation of a zigzag disclination can be attributed to the frustration between the normal alignment at the liquid crystal/air interface and the planar anchoring at the groove surface, together with the elastic constant for twist distortions smaller than those for other distortions. I further show that this zigzag disclination becomes asymmetric (that is, "zigs" become longer than "zags") when a chiral gas is blown onto it [2]. It responds to various chiral gas materials, and could be used as a simple sensor detecting the chirality of a gas sample. This work was done in collaboration with experimental colleagues Dr. Takuya Ohzono and Dr. Takahiro Yamamoto both from NRI, AIST, Tsukuba. [1] Ohzono and Fukuda, Nature Communications 3, 701 (2012). [2] Ohzono, Yamamoto and Fukuda, Nature Communications 5, 3735 (2014).