首页   按分类浏览 期刊浏览 卷期浏览 Ensemble-Averaged Dynamic Light Scattering from Polymer-Stabilized Liquid Crystals
Ensemble-Averaged Dynamic Light Scattering from Polymer-Stabilized Liquid Crystals

 

作者: Pei-Yuan Liu,   AlexM. Jamieson,   L.C. Chien,  

 

期刊: Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals  (Taylor Available online 2000)
卷期: Volume 348, issue 1  

页码: 187-205

 

ISSN:1058-725X

 

年代: 2000

 

DOI:10.1080/10587250008024806

 

出版商: Taylor & Francis Group

 

关键词: Polymer stabilized liquid crystal;Heterogeneous medium;Phase separation

 

数据来源: Taylor

 

摘要:

We report measurements of the viscoelastic parameters associated with the twist distortion of polymer-stabilized liquid crystal materials (PSLC), made by polymerizing 4,4′-bis-(acryloyloxy)-1,1′-biphenylene (BAB) and 4-butoxybenzyl 4-[6-(methacryloyloxyl-hexyloxy]benzoate (BMB6) to form fibrous networks in a nematic liquid crystal solvent (4′-phenyl-4-cyanobiphenyl, 5CB). By varying the BAB/BMB6 ratio, the twist elastic constant, K22, and viscosity, γ1, were investigated over a range of crosslink densities using electric-field-dependent dynamic light scattering (EFDLS). In PSLC samples, the formation of a highly-crosslinked, phase-separated polymer network can lead to optically heterogeneous behavior of the EFDLS data. Thus, it is necessary to evaluate the ensemble-averaged EFDLS relaxation function through spatial averaging. The results show that the polymer network causes a change in the twist relaxation rate, depending on the cross-link density of the specimens. The twist viscosity was found to increase with decrease in cross-link density, which appears to occur because higher cross-link density causes collapse of the gel fibers and less interaction between the fibers and nematic medium.

 

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