液晶薄膜於臨界點附近之比熱行為研究

Heat Capacity and Optical Reflectivity Measurement on 44COOBC Thin Films

賴子暉(Tzi-Huei Lai)

指導教授 ： 趙治宇

國立臺灣大學/理學院/物理研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.02502

摘要

近十年來，高解析度的比熱儀以及光反射的量測顯示液晶薄膜有逐層相變的趨勢。我們量測了44COOBC在SmA與HexB相變點附近的比熱行為，發現44COOBC與64COOBC存在許多相似的地方。由表面張力引發的相變行為，可能使得薄膜在低維度時產生與三維系統不同的行為。我們計算了相變所需熵的變化，發現熵與體積正比的關係可能在低維度會不存在。

關鍵字

液晶薄膜 ； 臨界現象 ； 比熱

並列摘要

High-resolution heat capacity and optical-reflectivity measurements had been conducted near the smectic-A to hexatic-B transition in thin free-standing films of the liquid crystal compound 54COOBC and 64COOBC. It is surprise that dependence on film thickness of the integrated magnitude of the heat-capacity anomalies as the films undergo layer-by-layer transitions between 54COOBC and 64COOBC are different. Hence we measure 44COOBC at the same circumstance, and try to figure out how the effect on an alkyl in the liquid crystal compound.

並列關鍵字

free standing film ； critical point ； heat capacity

參考文獻

[3] S. Martellucci, and A. N. Chester, Phase Transitions in Liquid Crystals (1991).

[4] P.S. Pershan, Structure of Liquid Crystal Phases, world scientific (1988).

1135 (1981).

Rev. Lett. 77, 2750 (1996).

[7] N. Goldenfeld, Lectures on Phase Transitions and the Renormalization Group