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The Study of Surface Property of Polyimide Liquid Crystal Alignment Thin Films by Means of Reflection Anisotropy Spectroscopy

The purpose of this thesis is to study the relation between surface optical anisotropy of polyimide thin film with different rubbing strength and liquid crystal alignment by means of reflection anisotropy spectroscopy (RAS). We discuss the surface properties of rubbed polyimide thin film by measuring the surface roughness, surface free energy and pretilt angle.
RAS is a non-contact optical probe of surfaces. It measures the difference in reflectance of normal incidence linearly polarized light between two orthogonal directions in the surface plane, and we can obtain the surface character of sample by analyzing the signals.
It is isotropic of polyimide thin film surface without rubbing, and reflection anisotropy (RA) signal is zero. The non-zero RA signal, i.e. anisotropic of surface, is revealed because of rubbed polyimide thin film surface. The RA signal is increasing with an increase in rubbing strength. In the results, we found that the pertilt angle is increasing with a decrease in surface free energy, and discovered the correlation between RA signal strength of characteristic wavelength and pretilt angle of liquid crystal at the rubbed polyimide thin film.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0818110-002850
Date18 August 2010
CreatorsHong, Jia-huang
ContributorsShin-jung Bai, Wen-jun Zheng, Tsung-hsien Lin, Chi-huang Lin
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-0818110-002850
Rightsoff_campus_withheld, Copyright information available at source archive

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