Thermally controllable reflective characteristics from rupture and self-assembly of hydrogen bonds in cholesteric liquid crystals.
A cholesteric liquid crystal (Ch-LC) composite, made of a series of cholesteryl esters, a nematic LC, and a hydrogen bond (H-bond) chiral dopant (HCD), was prepared and filled into a planar treated cell. When the cell was heated, the selective reflection of the cell exhibited an unusual blue shift. One of the reasonable mechanisms was that the helical twisting power (HTP) value of cholesteryl esters increased with an increasing temperature. The other one was that the H-bonds of HCD were ruptured when the temperature was above 60.0 degrees C and HCD was split into two kinds of new chiral dopants, which made the HTP value of the chiral dopants change a lot, thus changing the pitch length of the composite greatly. On the basis of this mechanism, a novel thermally controllable reflective color paper could be achieved.
Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Wang
W
Hu
Hui
H
Cao
Li
L
Song
Haiyan
H
Zhao
Sijin
S
Li
Zhou
Z
Yang
Huai
H
Yang