Thermodynamic and Interfacial Properties of DTABr/CTABr Mixed Surfactant Systems in Ethanolamine/Water Mixtures: A Conductometry Study

Table 3

The degree of counterion binding, thermodynamic function, micellar composition, interaction parameters, and critical micelle concentration of the DTABr + CTABr in 0.4% ethanolamine.

Temp (K)	𝛼DTABr	β	Δ𝐺^𝐸 (J/mol)	Δ𝐻𝑀 (J/mol)	Δ𝑆𝑀 (J/mol⋅K)	Δ𝐺𝑀 (J/mol)	𝜒1	𝛽12	𝑓DTABr	𝑓CTABr	cmc* (mM)
298.1	0.1	0.78	−3040.6	−3040.6	4.47	−4374.2	0.229	−4.95	0.016	0.694	0.535
	0.2	0.72	−2716.1	−2716.1	4.62	−4094.0	0.244	−5.94	0.033	0.702	0.596
	0.3	0.71	−2329.3	−2329.3	4.66	−3720.3	0.249	−5.03	0.058	0.732	0.706
	0.4	0.63	−1917.7	−1917.7	4.64	−3308.1	0.247	−4.14	0.097	0.774	0.797
	0.5	0.55	−2586.2	−2586.2	5.09	−4106.4	0.303	−4.94	0.091	0.635	0.872
	0.6	—	—	—	—	—	—	—	—	—	—
303.1	0.1	0.67	−3194.3	−3194.3	4.51	−4562.3	0.233	−7.09	0.015	0.680	0.520
	0.2	0.65	−3233.4	−3233.4	4.79	−4685.5	0.263	−6.62	0.027	0.632	0.524
	0.3	0.62	−2513.2	−2513.2	4.72	−3946.2	0.256	−5.24	0.054	0.709	0.679
	0.4	0.58	−2525.1	−2525.1	4.90	−4012.8	0.277	−5.00	0.073	0.681	0.738
	0.5	0.57	−2490.2	−2490.2	5.05	−4023.5	0.297	−4.73	0.097	0.658	0.833
	0.6	—	—	—	—	—	—	—	—	—	—
308.1	0.1	0.71	−3733.6	−3733.6	4.63	−5160.9	0.245	−7.87	0.011	0.623	0.451
	0.2	0.69	−3616.1	−3616.1	4.88	−5121.7	0.275	−7.09	0.024	0.586	0.478
	0.3	0.57	−2879.2	−2879.2	4.84	−4372.2	0.269	−5.71	0.048	0.660	0.620
	0.4	0.54	−3006.2	−3006.2	5.04	−4559.9	0.295	−5.64	0.061	0.611	0.647
	0.5	0.51	−2864.9	−2864.9	5.14	−4451.6	0.310	−5.22	0.083	0.604	0.750
	0.6	—	—	—	—	—	—	—	—	—	—
313.1	0.1	0.75	−3627.1	−3627.1	4.63	−5075.6	0.245	−7.54	0.014	0.636	0.481
	0.2	0.64	−3114.6	−3114.6	4.72	−4591.7	0.255	−6.30	0.030	0.664	0.559
	0.3	0.63	−2764.0	−2764.0	4.79	−4263.8	0.263	−5.48	0.051	0.685	0.660
	0.4	0.61	−2237.9	−2237.9	4.76	−3730.5	0.260	−4.47	0.087	0.739	0.711
	0.5	—	—	—	—	—	—	—	—	—	—
	0.6	—	—	—	—	—	—	—	—	—	—

∗Critical micellar concentration.