MOLECULAR-DIFFUSION AND DRAINAGE OF THIN LIQUID-FILMS STABILIZED BY BOVINE SERUM-ALBUMIN TWEEN 20 MIXTURES IN AQUEOUS-SOLUTIONS OF ETHANOL AND SUCROSE

The drainage characteristics and surface lateral diffusion properties of thin liquid films (foam lamellae) formed by BSA (bovine serum album in) and Tween 20 were studied using optical microscopy including epi-i llumination and fluorescence recovery after photobleaching. The concen trations of the surfactant and protein at the aqueous phase interface, the composition of the interface (BSA, Tween 20, and BSA-Tween 20 mix tures), and the aqueous phase composition (1 M ethanol and 0.5 M sucro se) were the variables studied. This study has revealed many complicat ed effects arising from film-film and film-subphase interactions as a function of the variables studied. The interactions between Tween 20 a nd BSA at the interface were found to dependent not only on the interf acial composition but also on the subphase composition.