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Seminary:"Slippery when wet: Viscosity reduced substrates for high performance liquid crystal displays"

dal 09/11/2018 alle 14:00 al 09/12/2018

Dove Aula 1 Dipartimento CHIMIND, Viale Risorgimento 4, Bologna

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Which will be given by:


Dr. Lee Kuang{Wu, Department of Physics, Kyoto University, Kyoto, Japan


email: hlee.kuangwu.3a@kyoto-u.ac.jp

 

The conventional liquid crystal technology (LCD) has dominated the display market for decades,
until recent years. New types of optical device, such as solid{state organic light{emitting diode
(OLED), have been challenging this long{established with a desired faster material response
(LCD: 5 ms vs OLED: 0:1 ms). Facing the survival challenge, new high performance LCD is
expected to achieve fast response by reduced LC rotational viscosity on the substrates, hence
this new device could also be driven with smaller voltage. The proposed concept was rst
prototyped by polymercoating on glass substrates, for which it leads to a slippery surface
with reduced rotational viscosity. For practical commercial usages, a second type of slippery
substrates is also achieved by adding impurity dyes in LC samples. The accumulation of dye
molecules on substrates, for which it is a wetting process, isolates the original anchoring eect
from substrates hence creates free rotational environment for LC molecules. This new type of
substrates are being prepared for the use of next generation LCD. As a counterpart study to
the experiments, a modied mesoscopic liquid crystal Q tensor model is applied to simulate the
LC dynamics under external elds. The polymercoated/impurity{induced slippery surfaces are
modeled by a numerical polymer layer, and this approach gives us informations of the substrate
conditions, when comparing with experimental data. The usages of generated LC bulk ows,
for potential application on LC micro uidics, will also be discussed in this talk.