In-situ monitoring of a film preparation process for hydroxypropyl cellulose cast from isotropic aqueous solution using microdielectrometry |
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Authors: | Katsufumi Tanaka Yuichiro Tanabe Takatoshi Morina Ryuichi Akiyama |
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Affiliation: | a Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japanb Department of Polymer Science and Engineering, Kyoto Institute of Technology, Kyoto 606-8585, Japan |
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Abstract: | Solid cast films with polydomain textures were prepared on a glass substrate with transparent interdigitated electrodes from an isotropic aqueous solution of hydroxypropyl cellulose via its liquid crystalline phase under the sinusoidal electric field with small amplitude and frequency of 0.05 V µm-1 and 105 Hz, respectively. The process was monitored using microdielectrometry as well as polarised optical microscopy. The apparent dielectric constant εr' and loss factor εr' sensitively changed with time depending on the process conditions. On the other hand, the logarithmic relation between εr' and εr' showed a single curve, when they were normalised by an effective portion of the electrostatic energy density estimated using each solid-film thickness. The conversion to the solid film was estimated during the process based on the concentration dependences of εr' and εr'. Characteristic times were reported for the onset of the biphasic phase, fully developed cholesteric phase and termination of the process. |
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Keywords: | hydroxypropyl cellulose aqueous solutions cast films in-situ monitoring dielectric properties optical observations polydomain textures |
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