鐵電型液晶材料光熱相變研究; Phase transition in ferroelectric liquid crystal

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7307

Title:	鐵電型液晶材料光熱相變研究;Phase transition in ferroelectric liquid crystal
Authors:	陳虹穎;Horng-Ying Chen
Contributors:	物理研究所
Keywords:	相變;liquid crystal;phase transition
Date:	2003-06-26
Issue Date:	2009-09-22 10:54:51 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	利用高精密的比熱量測系統量測自由懸浮薄膜C7鐵電型液晶材料從Sm-A到Sm-C相變化過程中比熱趨勢的變化，我們發現比熱變化的趨勢和厚度的變化有相當程度的相依性，仔細分析熱滯量後發現這個相變隨著維度的減少而出現從一階相變到二階相變的過渡情形，這個實驗的結果和液晶材料MDW1397的結果相當類似。此外，我們觀察了C7這個液晶材料中從Sm-C到Sm-G的相變，這個相變出現了逐層相變的現象，且藉由分析此現象，我們發現了Thermal- Casimir force 在這個相變中扮演了重要的角色。 High-resolution heat-capacity measurements have been conducted near the Sm-A to Sm-C transition in free-standing films of liquid-crystal compound C7. We find that the profiles of associated heat-capacity anomalies are strongly thickness-dependent and exhibit a novel crossover behavior in reduced dimensions. This result is similar to the observed in MDW1397 liquid-crystal films. Furthermore, heat-capacity measurements have provided the direct confirmation of surface transitions from Sm-C immediately to the Sm-G phase in C7. The molecular interactions are found to be Thermal-Casimir force.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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