ADSORPTION OF PROTEINS AT LIQUID FLUID INTERFACES/

A thermodynamic treatment of protein adsorption layers is presented an d an equation of state of the interfacial layer is derived, Only by as suming different models for the activity coefficients in the interfaci al layer different are models derived considering ideal and nonideal e ntropy and enthalpy of mixing, As special cases, well-known equations from other authors are obtained which are frequently used for the desc ription of surfactant and polymer adsorption, Concerning the configura tion of adsorbed protein molecules, i.e., number of protein segments a dsorbed, the composition of the adsorption layer is caused by a self-r egulation process which is mainly influenced by the chain flexibility and determines the surface pressure, Only four basic parameters descri be the adsorption equilibrium of the protein, A sufficiently good agre ement between literature data and the model is obtained, although best -fit procedures do not exist so far and the isotherm parameters were a djusted only manually. (C) 1996 Academic Press, Inc.