Temperature dependence of rotational viscosity for liquid crystal 8CB

• Main Authors: Shyh-Wei Jeng, 鄭世偉
• Other Authors: Ru-Pin Pan
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/74080932903077118042

碩士 === 國立交通大學 === 電子物理學系 === 83 === This thesis is to determine the temperature dependence of rotational viscosities for liquid crystal 4`-n-octyl-4- cyanobiphenyl(8CB) with consideration on the flow effect caused by rotation.We first measure and then compare the relaxation times under magnetic fields of films with and without a free surface at various temperatures.By these data, we can deduce the rotational viscosity as a function of temperature, and then compare with existing theories from statistical considerations. Since the relaxation times have to be measured under various magnetic fields and temperatures,we have automated our system by using personal computers to control the experimental conditions and to take the datd. By comparing the Osipov- Terentjev theory with our experimental results, the activation energy,mean-field potential of liquid crystal 8CB are obtained.