DETERMINATION OF AGGREGATION NUMBERS AND IONIZATION DEGREE OF MICELLES USING SURFACE-TENSION ISOTHERMS OF MALEIC-ACID MONO[2-(4-ALKYLPIPERAZINYL)ETHYL ESTERS]
R. Wustneck et al., DETERMINATION OF AGGREGATION NUMBERS AND IONIZATION DEGREE OF MICELLES USING SURFACE-TENSION ISOTHERMS OF MALEIC-ACID MONO[2-(4-ALKYLPIPERAZINYL)ETHYL ESTERS], Langmuir, 10(11), 1994, pp. 3955-3958
By use of the slopes of surface tension isotherms at concentrations ab
ove and below the critical micelle concentration, the aggregation numb
ers of homogous maleic acid mono[2-4(4-alkylpiperazinyl)ethyl esters]
micelles are determined at pH = 6.2, where these surfactants exist in
the betain-like form. For pH values at which the adsorption of almost
only one surface active ionic component of these surfactants is guaran
teed, the degree of counterion binding is determined for two samples o
f the homologous series. The results obtained show that the method app
lied to determine these values from surface tension measurements opens
a new possibility to interpret surface tension isotherms. The method
needs, however, very accurate measurements because even small deviatio
ns may alter the results significantly.