The kinetics of liquid drainage from colloidal gas aphrons (CGA) was investigated at various concentrations of sodium dodecyl sulphate (SDS), hexadecyltrimethyl ammonium bromide (HTAB), and Tween 80, respectively, under the conditions of different temperatures. The liquid drainage rates were determined by reading the volume of the liquid drained as a function of time. Effect of the surfactant type, concentration and system temperature on the kinetic stability of CGA was discussed. Drainage behavior was fitted by the empirical equation: V_t＝V_maxtⁿ/(Kⁿ＋tⁿ), where V_t refers to the volume of drained liquid at time t, V_max denotes the maximum volume of drained liquid, n describes the sigmoidal character of the curve and K is equal to the half-life t_1/2 of drainage. Rate constant k_d and the half-life t_1/2 of liquid drainage could be calculated from parameters V_max, K, and n. This kinetic model was tested with the use of the Arrhenius equation, which relates the logarithm of the kinetic constant (ln k_d) linearly to the reciprocal of the elevated temperature (T^－1). Two distinct stages of CGA drainage determined by two independent mechanisms were identified from analysis of the rate of liquid drainage as a function of time.

Key words: colloidal gas aphron, drainage, kinetic model