88.4 Surface adsorption of solution 8.4.2 Gibbs adsorption isotherm n:+n?+n b B nterface Interphase Interfacial regioninterface Interphase Interfacial region   S S’ a a’ b b’ 8.4.2 Gibbs adsorption isotherm    ni = ni + ni + ni    ni = ni − ni − ni i n A   = §8.4 Surface adsorption of solution