Transient phenomena of relaxation from electric‐field‐induced nematic phase to cholesteric phase
作者:
S. K. Kwok,
York Liao,
期刊:
Journal of Applied Physics
(AIP Available online 1978)
卷期:
Volume 49,
issue 7
页码: 3970-3975
ISSN:0021-8979
年代: 1978
DOI:10.1063/1.325407
出版商: AIP
数据来源: AIP
摘要:
In certain mixtures of nematic and cholesteric liquid crystals, it is found that the metastable final state in an electric‐field‐induced nematic to cholesteric transition depends on the turnoff rate of the applied voltage. Experimental evidence sugests that two processes, i.e., helix winding and Freedericksz transition type molecular reorientation, may be involved. Relaxation times for both are estimated theoretically and compared with experimental results. An overall relaxation process is also proposed phenomenologically and the predictions compare favorably with the temporal data. The prerequisites on the threshold fields and relaxation times for this phenomenon are deduced. It is believed that this new observation may help explain the transient behavior in a nematic‐cholesteric phase transition and may promise some practical applications.
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