Formation of optically anisotropic alginic acid gels under dc electric fields

F. Yokoyama, T. Fujino, Kunio Kimura, Y. Yamashita, K. Nagata, H. Mihashi

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

It was found that optically anisotropic disk-shaped gels of alginic acid were formed by a new gelation system which was based on the electrolysis of water. In this system, electrodes composed of a central anode and a surrounding cathode of 30 mm radius were dipped in 0.6-2.6 wt% sodium alginate solutions, and d.c. electric fields of 1.7-6.7 V/cm were applied. The ion exchange and sodium ion transfer towards the cathode gave rise to formation of the alginic acid gel around the anode, combined with water transfer to the sol, i.e. dehydration, which was assumed to originate from osmotic pressure induced by a one-sided distribution of the ionic solutes. In the case of the 0.6 wt% solution, almost non-birefringent gels were formed and transformed to strongly birefringent gels, where the chains were deduced to be oriented parallel to the side surface of the gels. In the case of the 1.3 or 2.6 wt% solution, only the latter types of gels were formed. With increasing voltage, the gels were largely deformed and the macroscopic anisotropy was much disordered. It was revealed that the strongly birefringent gels were formed only when the alginic acid concentration was elevated above a critical value through dehydration.

Original languageEnglish
Pages (from-to)229-234
Number of pages6
JournalEuropean Polymer Journal
Volume34
Issue number2
Publication statusPublished - Feb 1 1998

Fingerprint

Alginate
Gels
Electric fields
gels
acids
electric fields
Dehydration
dehydration
Anodes
Cathodes
anodes
cathodes
sodium
Sodium alginate
osmosis
alginic acid
Water
gelation
Polymethyl Methacrylate
Gelation

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics

Cite this

Yokoyama, F., Fujino, T., Kimura, K., Yamashita, Y., Nagata, K., & Mihashi, H. (1998). Formation of optically anisotropic alginic acid gels under dc electric fields. European Polymer Journal, 34(2), 229-234.

Formation of optically anisotropic alginic acid gels under dc electric fields. / Yokoyama, F.; Fujino, T.; Kimura, Kunio; Yamashita, Y.; Nagata, K.; Mihashi, H.

In: European Polymer Journal, Vol. 34, No. 2, 01.02.1998, p. 229-234.

Research output: Contribution to journalArticle

Yokoyama, F, Fujino, T, Kimura, K, Yamashita, Y, Nagata, K & Mihashi, H 1998, 'Formation of optically anisotropic alginic acid gels under dc electric fields', European Polymer Journal, vol. 34, no. 2, pp. 229-234.
Yokoyama F, Fujino T, Kimura K, Yamashita Y, Nagata K, Mihashi H. Formation of optically anisotropic alginic acid gels under dc electric fields. European Polymer Journal. 1998 Feb 1;34(2):229-234.
Yokoyama, F. ; Fujino, T. ; Kimura, Kunio ; Yamashita, Y. ; Nagata, K. ; Mihashi, H. / Formation of optically anisotropic alginic acid gels under dc electric fields. In: European Polymer Journal. 1998 ; Vol. 34, No. 2. pp. 229-234.
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