Physicochemical Studies on the Interaction between Sodium Dodecyl Sulfate and Methylene Blue in Methanol-Water Mixed Solvent Media

Table 1

Values of the degree of ionization (α), CMC (by conductometry and tensiometry), and Gibbs free energy of micellization () of SDS in different volume fractions of methanol-water at 298.15 K.

Volume fraction of methanol	Degree of ionization (α)		CMC (mM) by conductometry		CMC (mM) by tensiometry		(kJ·mol^−1) by conductometry		CMC (mM) by conductometry [55]	CMC (mM) by tensiometry [56]
	a	b	a	b	a	b	a	b	a	a
0.1	0.464	0.485	8.30	7.60	8.50	7.60	−33.31	−34.30	8.50	9.20
0.2	0.479	0.511	9.40	9.10	9.50	9.0	−32.29	−32.79	9.60	10.30
0.3	0.518	0.541	11.08	10.33	11.4	10.56	−30.62	−31.42	∼11.0	11.70

a = calculated value in the absence of methylene blue. b = calculated value in the presence of methylene blue.