Non-ionic surfactant interactions in aqueous gelatin solution: A physico-chemical investigation

In the present study, density and sound velocity measurements of non-ionic surfactant Triton X-100 (TX-100) in aqueous solutions of gelatin have been carried out over a wide temperature range (20-40 degrees C). Molar volume (phi(v)) has been calculated from density measurements and various acoustical parameters such as apparent adiabatic compressibility (beta) and apparent molar compressibility (phi(k)) have been calculated from the sound velocity data in order to account for the consequences of protein-surfactant interactions. Negative values of phi(v) over an entire temperature range suggest that the protein-surfactant interactions are predominantly hydrophobic. Initial sharp increase in (phi(v)) values at low surfactant concentration indicates some hydrophilic interactions as well and leveling off at higher surfactant concentration could be due to self aggregation of TX-100 to form micelles. Further information to this effect has been obtained by evaluating activation energy parameters following viscosity studies. UV-Vis studies have also been carried out in case of ternary Protein-Surfactant-Water system by varying TX-100 concentration in the range (0.00043 M-0.16756 M). (C) 2011 Elsevier B.V. All rights reserved.