Abstract
The cloud point (CP) of a mixture of Tween 80 (Tw 80) and neomycin sulphate (NS) was measured in an aqueous medium containing electrolyte (NaCl, NaNO
3
, and Na
2
SO
4
). The CP of Tw 80 decreased when Tw 80 concentration increased. For various concentrations of Tw 80 (1.53 × 10
-2
, 3.05 × 10
-2
, and 6.11 × 10
-2
mol.kg
-1
), CP values of the solution decreased with increasing additions of NS. CP values of NS+Tw 80 mixtures also decreased upon the addition of salts, following the trend: CP
Na
2
SO4
> CP
NaNO3
> CP
NaCl
. Thermodynamic variables including standard-free energy (∆G
0
c), standard enthalpy (∆H
0
c), and standard entropy (∆S
0
c) of clouding as well as thermodynamic properties of transfer during phase transition were also determined. A linear relationship between enthalpy change (∆H
0
c) and entropy change (∆S
0
c) with an R
2
value of 0.9997-1.00 was obtained for the Tw 80+ NS mixture in aqueous electrolyte media.