Tuning of Coacervate Phase Behavior of Polyoxyethylene (4) lauryl ether
in Aqueous Alcoholic Solution: Investigation of Thermodynamics
Abstract
The influence of various additives on the coacervate phase behaviour of
micellar solution of non-ionic surfactant was investigated. Above the
critical micelle concentration, nonionic surfactant in aqueous solution
shows phase separation, at cloud point (CP), an increase in temperature
results in consequent changes in micellar size, shape, and interactions.
The addition of external material to surfactant solution changes the
temperature, at which clouding occurs. Herein we report how cloud point
changes in presence of alcohol as additives. The CP temperature of
non-ionic surfactant Polyoxyethylene (4) lauryl ether (Brij-30) was
investigated at various concentrations of surfactant in pure and
additives mixed systems. The results demonstrate that the CP of pure
Brij-30 surfactant shows a decreasing trend with increasing surfactant
concentration from 1 to 10 % (w/v) in a 22% aqueous ethanolic medium.
Simultaneously the CP values of Brij-30 with n-alcohols show an
increasing trend in the presence of C3OH and C4OH chain length alcohols,
due to the fact that they remain in the solution helps the formation of
expanded water structures hence favoring micelle hydration, while the
presence of C5OH, C6OH and C7OH chain length alcohols showing decreasing
trend due to increasing in micelle size. These changes in CP values of
Brij-30 in presence of various n-alcohols are useful to study the effect
of the structure of additives on the stability of micelle. The stability
of micelle aggregation was also discussed by using foam ability and foam
stability. The “Phase Separation Model “is useful for calculating
thermodynamic parameters of clouding