Design of Polysaccharide-based New Materials Exhibiting Magnetic and Electromagnetic Functions.by Use of Ion-associated Chelation and Gelation Characteristics of Carbohydrate Polymers

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Polysaccharide-based new materials ehibiting magnetic and electromagnetic functions were designed by, utilizing ion-associated chelation and gelation characteristics of carbohydrate polymers. The following results are worth noting.1.Magnetic Composites of Alginate/Poly vinyl alcohol) with Iron Oxide:Alginate-based gels containing iron oxides were prepared successfully by an in situ synthesis technique. Alginate was crosslinked in iron salt aqueous solution, and' the resulting gels were immersed into different alkaline solutions, whereupon i.on-exchanged gels were obtained. The gel samples were treated with an oxidizing agent, then dried in frozen state. SQUID magnetometry revealed that the dried gels showed superparamagnetism or ferromagnetism at room temperature, depending on the sort of metallic cation in the alkali treatment. IPN-type alginate/poly(vinyl alcohol) composites containing ion oxides were also prepared by modifying the above method. 'The, dynamic viscoelastic property of the composites was examined in gelatinous state, in addition to SQUID measurements.2.Magnetic Composites of Carrageenan -Iron Oxide:Carrageenan-based magnetic composites were prepared via in situ synthesis, of iron oxides in a similar way stated above. Electron microscopic observations and magnetometry measurements were conducted. It was found that almost alt the composites exhibited superparamagnetic character at 298K, and that magnetite and/or maghemite particles were dispersed in a scale less than several tens of nanometers in the interior as well as on the inner surface of fibrillar entities constituting the carrageenan matrix.3.Mesoscopic Systems of Cellulose Derivative/Inorganic Salt Ions:Mesoscopic structural characteristics of aqueous (hydroxypropyl)cellulose solutions and gels containing salt ions were made clearer. An electrooptical function was explored to control externally the reflective coloration and turbidity of the mesomorphic solutions and networks.