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The study of control the molecular arrangement of liquid crystals using dye-doped polydimethylsiloxane thin film

Nowadays, the common method to make an alignment layer of
liquid crystal display is rubbing Polyimide (P.I.) thin film, Unfortunately,
the rubbing method will reduce the yield of LCDs because of the particles,
electrons, etc. created during rubbing on the surface of PI film. therefore
many effort have been made to develop the non-contacting method such
as photo alignment, plasma alignment, etc. This research focus on the
non-contacting method, we hope it will reduce many pollution compared
to rubbing alignment.
Comparing with PI, polydimethylsiloxane (PDMS) possess higher
transparency, batter stability in thermal and chemical, and lower surface
free energy about 19 mJ/m^2. Due to the low surface free energy, PDMS
can be used as a vertical alignment layer without any surface treatment.
Methyl Red (MR) PDMS mixed with PDMS will be used as an alignment
layer in this experiment. And the rod-like azo-dye will change its
molecular to rotate because the absorption of linear polarized light. By
changing the s MR to rotate, we can obtain a
micro groove structure
on PDMS surface and control the direction
of liquid crystals further.
Xenon lamp(100nm-1200nm) and the ultraviolet ray lamp
(300-500nm) were used in this experiment for thin film. Samples were
exposure with different incident angle and intensity of light, respectively,
and discussed with different temperature as a factor. According to atomic
force microscope ( AFM ) result, we can obtain a PDMS surface with
micro groove structure by using Xe lamp and ultraviolet ray, and we can
observe the changing tilt angle of liquid crystals by polarized optical
microscope (POM).

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0727110-233625
Date27 July 2010
CreatorsLee, Yu-Shiuan
ContributorsTsung-Hsien Lin, Chi-Huang Lin, Shin-Jung Bai, Wen-Jun Zheng
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0727110-233625
Rightsunrestricted, Copyright information available at source archive

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