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 language | English |
|---|---|
| Pages (from-to) | 229-234 |
| Number of pages | 6 |
| Journal | European Polymer Journal |
| Volume | 34 |
| Issue number | 2 |
| Publication status | Published - Feb 1 1998 |
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ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
Cite this
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 journal › Article
}
TY - JOUR
T1 - Formation of optically anisotropic alginic acid gels under dc electric fields
AU - Yokoyama, F.
AU - Fujino, T.
AU - Kimura, Kunio
AU - Yamashita, Y.
AU - Nagata, K.
AU - Mihashi, H.
PY - 1998/2/1
Y1 - 1998/2/1
N2 - 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.
AB - 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.
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UR - http://www.scopus.com/inward/citedby.url?scp=0042731350&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0042731350
VL - 34
SP - 229
EP - 234
JO - European Polymer Journal
JF - European Polymer Journal
SN - 0014-3057
IS - 2
ER -