Abstract: The effects of n-hexanol on the micellization of quaternary ammonium dimeric surfactants (C12-s-C12•2Br,s=3,4,6) have been examined using conductivity and steady fluorescence measurements.The results showed that the critical micelle concentration cmc decreases with the addition of n-hexanol.The larger s,the stronger the effect.The dimeric surfactant and n-hexanol form the mixed micelles with the alkyl chains of n-hexanol molecules penetrating into the micelle interior and with hydroxyl groups lie in the palisade layer of the micelle.At the same concentration of n-hexanol in aqueous solution,the molar fraction of n-hexanol in the mixed micelle is almost the same for different s.The ionization degree of the mixed micelle increases with increasing n-hexanol concentration.

Key words: Quaternary-ammonium dimeric surfactants, n-hexanol effects, 　Micellization