The dimerization of methylene blue (MB) in organized molecular assemblies including micelle, O/W microemulsion and lamellar liquid crystal was investigated. On the basis of the peak absorption values of the visible spectra of MB, the dimerization constants and the molar absorption coefficients of the monomer and the dimer of MB were calculated. The results suggest that for a given total concentration of MB there are less monomer in micelle system than in O/W microemulsion system while the highest concentration of monomer is found in the lamellar liquid crystal system. Thus the lamellar liquid crystal system appears to be the ideal medium to acquire more MB monomers.

Key words: METHYL THIONINE CHLORIDE, ACCUMULATE, DIMER, CYCLOVOLTAMGRAPH