Papers by Author: Naoko Tomita

Abstract: Anisotropic gelation has been studied by immersing chitosan in aqueous acetic acid sandwiched by a pair of square cover glasses into aqueous sodium hydroxide. The shape of the gel front line initially remained a square, whereas it approached a circle with immersion time. The time course of the distance between the side of the cover glasses and the gel front line x_s was expressed initially as scaled proportional relationship (x_s/L)² =2K(t/L²), where t is the immersion time, L; the length of the side of the cover glasses and K; a constant. The characteristic behavior was independent of chitosan concentration.

Abstract: We have prepared an anisotropic hydrogel with birefringence by means of dialysis method and analyzed the dynamics of the gel-forming process using purified chitosan with the degree of deacetylation at 100%. The dynamics was expressed well by a theory based on “moving boundary picture”(Nobe, Dobashi and Yamamoto, Langmuir 2005).