电场作用下5CB液晶分子的近壁面层黏弹性的QCM研究

熊毅; 张向军; 张晓昊; 温诗铸

doi:10.7498/aps.59.7998

摘要

利用石英晶体微天平(quartz crystal microbalance,QCM)研究了电场对5CB液晶分子的近壁面层黏弹性的影响.对QCM结果的分析发现,电场作用对液晶的黏度影响分为两部分,通过建立含吸附膜的双层膜模型,分析了QCM的两部分结果,发现电场对近壁面吸附层及体相层的影响是不同的.根据QCM的双层膜模型,对近壁面层液晶分子的黏弹性及膜厚进行了定量的分析计算,结果表明5CB在石英晶体上电极附近有一层约100nm厚的近壁面吸附层,其复剪切黏度随电场强度的增加而减小,这与5CB液晶的体相黏度变化规

关键词:

Abstract

The influence of electric field on near-interface 4-pentyl-4'-cyanobiphenyl(5CB) liquid crystal (LC) is investigated with quartz crystal microbalance (QCM). The results of QCM show that the process of frequency shifting with electric field, which reflects the viscoelasticity change of 5CB, can be divided into two parts. Then the two-layer model of 5CB is proposed to illuminate the results of QCM, thereby indicating that the effect of electric field on near-interface layer is different from on bulk layer. Quantitative analysis is carried out with two-layer model of QCM, which indicates that there is a near-interface layer of about 100nm, adsorbed on the upper electrode of quartz crystal. The complex shear viscosity of the near-interface layer decreases with electric field strength increasing, which is opposite to the rule of bulk viscosity of 5CB.

Keywords:

near-interface 4-pentyl-4'-cyanobiphenyl (5CB) liquid crystal /
quartz crystal microbalance /
near-interface layer /
viscoelasticities

作者及机构信息

1.
清华大学摩擦学国家重点实验室,北京 100084

基金项目: 国家自然科学基金(批准号:50975154,50730007),国家重点基础研究发展计划(批准号:2007CB607604),国家自然科学基金委创新研究群体(批准号:50721004).

Authors and contacts

1.
State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China

参考文献

[1]	Van Aerle N A J M, Barmentlo M, Hollering R W J 1993 J. Appl.Phys. 74 3111
[2]	Tsvetkov V A 2005 Mol. Cryst. Liq. Cryst. 436 1157
[3]	Arno D, Diethelm J 2002 Appl.Phys.Lett. 80 4750
[4]	Shen Mingwu, Luo Jianbin, Wen Shizhu, Yao Junbin 2001 Chinese.Sci.Bulletin 46 603(in Chinese)[沈明武、雒建斌、温诗铸、姚俊斌 2001 科学通报 46 603]
[5]	Mu Q Q, Liu Y J, Hu L F, Li D Y, Cao Z L, Xuan L 2006 Acta Phys. Sin. 55 1055(in Chinese)[穆全全、刘永军、胡立发、李大禹、曹召良、宣丽 2006 物理学报 55 1055]
[6]	Liu H W, Tang K B 1996 Acta Phys. Sin. 45 480 (in Chinese)[刘和文、唐凯斌 1996 物理学报 45 480]
[7]	Martinoty P, Candau S 1971 Mol. Cryst. Liq. Cryst. 14 243
[8]	Kiry F, Martinoty P 1977 J. Phys. (Paris) 38 153
[9]	Inoue M, Yoshino K 2002 Jpn. J. Appl. Phys. 91 2798
[10]	De Gennes P G 1974 The Physics of Liquid Crystals (Oxford University Press, London)
[11]	Martin P C, Parodi O, Pershan P S 1972 Phys. Rev. A 6 2401
[12]	Muramatsu H, Iwasaki F 1995 Mol. Cryst. Liq. Cryst. 258 153
[13]	Kubono A, Akiyama R 2006 Mol. Cryst. Liq. Cryst. 445 213
[14]	McHale G, Lucklum R 2000 J. Appl. Phys. 88 7304
[15]	Reed C E, Kanazawa K K, Kaufman J H 1990 J. Appl. Phys. 68 1993
[16]	Ankit R P, Bruce A K 2009 J. Pharm. Sci. 98 3108
[17]	Lelidis I 1998 Liq. Cryst. 25 531

施引文献

[1]	Van Aerle N A J M, Barmentlo M, Hollering R W J 1993 J. Appl.Phys. 74 3111
[2]	Tsvetkov V A 2005 Mol. Cryst. Liq. Cryst. 436 1157
[3]	Arno D, Diethelm J 2002 Appl.Phys.Lett. 80 4750
[4]	Shen Mingwu, Luo Jianbin, Wen Shizhu, Yao Junbin 2001 Chinese.Sci.Bulletin 46 603(in Chinese)[沈明武、雒建斌、温诗铸、姚俊斌 2001 科学通报 46 603]
[5]	Mu Q Q, Liu Y J, Hu L F, Li D Y, Cao Z L, Xuan L 2006 Acta Phys. Sin. 55 1055(in Chinese)[穆全全、刘永军、胡立发、李大禹、曹召良、宣丽 2006 物理学报 55 1055]
[6]	Liu H W, Tang K B 1996 Acta Phys. Sin. 45 480 (in Chinese)[刘和文、唐凯斌 1996 物理学报 45 480]
[7]	Martinoty P, Candau S 1971 Mol. Cryst. Liq. Cryst. 14 243
[8]	Kiry F, Martinoty P 1977 J. Phys. (Paris) 38 153
[9]	Inoue M, Yoshino K 2002 Jpn. J. Appl. Phys. 91 2798
[10]	De Gennes P G 1974 The Physics of Liquid Crystals (Oxford University Press, London)
[11]	Martin P C, Parodi O, Pershan P S 1972 Phys. Rev. A 6 2401
[12]	Muramatsu H, Iwasaki F 1995 Mol. Cryst. Liq. Cryst. 258 153
[13]	Kubono A, Akiyama R 2006 Mol. Cryst. Liq. Cryst. 445 213
[14]	McHale G, Lucklum R 2000 J. Appl. Phys. 88 7304
[15]	Reed C E, Kanazawa K K, Kaufman J H 1990 J. Appl. Phys. 68 1993
[16]	Ankit R P, Bruce A K 2009 J. Pharm. Sci. 98 3108
[17]	Lelidis I 1998 Liq. Cryst. 25 531

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