RELATIONSHIP BETWEEN STRUCTURE AND SOLUBILIZATION PROPERTIES OF SOME BISQUATERNARY AMMONIUM AMPHIPHILES

The effect of structure changes of two series of bis-quaternary ammonium salts, the so-called bola-amphiphiles, of N,N′-bis(alkyldimethyl)-α,ω-alkanediammonium dibromides type, where the alkyl chain had 8 to 16 carbon atoms and the connecting chain had 2 to 12 carbon atoms upon the solubilizing capacity and aggregation properties of their aqueous solutions was examined. From solubilization data the critical micelle concentration (CMC) was also determined. With N,N′-bis(alkyldimethyl)-1,6-hexanediammonium dibromides the solubilizing capacity as well as the CMC were linearly dependent upon structure changes. However, with N,N′-bis(decyldimethyl)-α,ω-alkanediammonium dibromides nonlinear relationships were observed with both characteristics related to structure changes. The maximum solubilizing capacity was observed with compound with n = 6 and 8 (m = constantly decyl) contrary to the CMC which was found to be maximal in the region of compounds with n = 4 to 6. The anomalous courses of these relationships were elucidated in terms of spatial arrangements of the micelles. © 1991.