Two-dimensional surface properties of the mixed film of α-methoxy poly(ethylene glycol) macromonomer with stearic acid at the air-water interface in absence and presence of SDS at different temperatures

The mixed film of macromonomer (molecular weight 460, acrylic ester of omega-methoxypoly(ethylene glycol)) with stearic acid has been investigated for surface properties in the absence and presence of SDS at the air-water interface using a Langumir film balance. The above experiments have been performed at different temperatures in order to understand the macromonomer stability and compatibility in mixed systems and to compute thermodynamic parameters. The macromonomer is found to form a thermodynamically stable mixed film with stearic acid at a molar ratio of 4:1 at 25 degrees C. Furthermore, in the presence of SDS, the compatibility between macromonomer and stearic acid films decreases, probably due to the greater dissolution of macromonomer in the bulk phase.