Abstract: The stability of the aqueous solution, surface activity, stability of the foam and foaming ability of the mixture, formed by mixing TX-100 (C_8H_(17)C_6H_4(OC_2H_4)_(9.8)OH; C_8ΦE_(9.8)) and its sulfate (C_8H_(17)C_6H_4(OC_2H_4)_(9.8)OSO_3Na; C_8ΦE_(9.8)S) with cationic surfactants (C_nH_(2n+1)+NC_5H_5Br; C_nPy, n=10, 12, 14; C_mH_(2m+1)N(CH_3)_3Br; C_mNM_3, m=16, 18), have been measured. The results show that it can not only form a stable aqueous solution of cationic-anionic surfactant mixture, but also promote the solubility of cationic surfactants very much when C_8ΦE_(9.8)S mix with cationic surfactants; The surface activity of the foam and the foaming ability of C_8ΦE_(9.8)S-C_nPy will reach the maximum when n equate to 12. The surface activity and the stability of the foma of C_8ΦE_(9.8)S-C_(18)NM_3 are much higher than that of C_8ΦE_(9.8)S-C_(18)NM_3, but the foaming ability of C_8ΦE_(9.8)S-C_(18)NM_3 is much higher than that of C_8ΦE_(9.8)S-C_(18)NM_3. Theoretical calculation shows that the attraction between C_8ΦE_(9.8)S and C_(18)NM_3 is much stronger than that between C_8ΦE_(9.8)S and C_(18)NM_3.

Key words: Miexd surfactants, TX-100, Alkylphenyl polyoxyethylene ether sufate salts, Cationic surfactants