物理化学学报 >> 1996, Vol. 12 >> Issue (08): 688-692.doi: 10.3866/PKU.WHXB19960804

研究论文 上一篇    下一篇

侧链型丙烯酸酯共聚物相变的正电子湮没谱研究

王文华,魏龙,张天保,何流,张树范,漆宗能   

  1. 中国科学院高能物理研究所,中国科学院核分析技术开放实验室,北京 100080|中国科学院化学研究所,北京 100080
  • 收稿日期:1995-12-21 修回日期:1996-03-25 发布日期:1996-08-15
  • 通讯作者: 魏龙

Phase Transition of Side Chain Liquid Crystal Polyacrylate Studied by Positron Annihilation Lifetime Spectra

Wang Wen-Hua,Wei Long,Zhang Tian-Bao,He Liu,Zhang Shu-Fan,Qi Zong-Neng   

  1. Laboratory of Nuclear Analysis Techniques,Institute of High Energy Physics,Academia Sinica,Beijing 100080|Institute of Chemsitry,Academia Sinica,Beijing 100080
  • Received:1995-12-21 Revised:1996-03-25 Published:1996-08-15
  • Contact: Wei Long

摘要:

利用正电子湮没技术对侧链型热致高分子液晶丙烯酸酯共聚物进行了变温相变研究.除实验标识出样品的相变温度点外,根据试样中自由体积随温度的变化关系,对高分子液晶材料内部立链、侧链以及介晶基元的相变行为特点进行了探讨,并就与小分子液晶变化特点的一些不同做了解释.

关键词: 正电子湮没, 高分子液晶, 自由体积

Abstract:

The results of positron annihilation studies on the side-chain polymer liquid crystals were obtained as a function of temperature. It is indicated that thermotropic liquid crystal has two phase transition points near 40℃ and 76℃ respectively. It is suggested that the first phase transition point is correspondent to the melting point of specimen and the second one is clearing point at which liquid crystal phase transits isotropic liquid phase. It can be concluded by the changes of Free-Volume at the phase transition points that the smectic state SA is in better ordered state than the other liquid crystals. The difference in the curves of o-Ps life-time with temperature between the liquid crystal and the liquid crystal polymer was explained.

Key words: Positron annihilation, Liquid crystal polymer, Free-Volume