Cooperative Interaction of Carboxymethyl Cellulose with C.I. Basic Red 18 in Aqueous Solution

Carboxymethyl Cellulose와 C.I Basic Red 18과의 협동적 상호작용

The binding isotherms of C.I. Basic Red 18 with carboxymethyl cellulose having various degrees of substitution were determined in an acetate buffer of pH 4.2 at 30℃ by a dynamic dialysis technique. The isotherms showed a sigmoidal binding which was increased with the increase of free dye concentration in solution. The results strongly suggest a cooperative mode of binding. In the interpretation of the results McGhee and von Hippel's theory considering cooperativeness in binding was used. The intrinsic binding constant K, the number of consecutive polymer residues occupied by a single dye molecule and the cooperativeness parameter were determined. A binding mechanism of CMC-dye was proposed.