The dynamic surface tension of the aqueous solutions of cetyltrimethylammonium bromide (CTAB), poly(diallyldimethylammonium chloride) (PDADMAC) and their mixed solution were measured in the case of slow stretching surface by the maximum bubble pressure method at 30℃. The adsorption of CTAB molecules follows a diffusion- kinetic-controlled adsorption mechanism. dynamic surface tension isotherm of aqueous PDADMAC solution exhibits a peculiar feature. Each of the four sections in isotherm corresponds a special adsorption period. Increasing surface tension at the beginning of adsorption may be responsible for the adsorption of excess water at the interface. The existence of an induction period can be explained by the adsorption barrier due to polymer molecular characteristics. A marked reduction in surface tension in the time period t~1

Key words: SURFACE TENSION, SURFACES ADSORPTION, SURFACTANTS