Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures
Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures
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DOI：
10.1088/0022-3727/33/24/316
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发表时间：
2000-12-21
影响因子：
3.4
通讯作者：
Radhakrishnan, P
中科院分区：
文献类型：
--
作者：
George, NA;Vallabhan, CPG;Radhakrishnan, P
本文报道了用激光诱导光声方法研究了某些商品化液晶混合物BL 001、BL 002、BL 032和BL 035的向列相到各向同性的转变。使用Rosencwaig-Gersho理论的实验数据的简单分析表明，所有这些化合物的热容量表现出尖锐的峰值作为样品的温度在整个过渡区的变化。此外，已注意到所有的混合物的光声信号振幅的实质性差异，在双相和各向同性相。增强的光散射特性可能是光声信号幅度在该阶段增强的原因。
We report on a laser induced photoacoustic study of the nematic-to-isotropic transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002, BL032 and BL035. A simple analysis of the experimental data using the Rosencwaig-Gersho theory shows that the heat capacities of all these compounds exhibit a sharp peak as the temperature of the sample is varied across the transition region. Also, substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases have been noticed for all the mixtures. The increased light scattering property of the nematic phase may be the reason for the enhanced photoacoustic signal amplitude in this phase.