Study on Measuring of Dynamic Interfacial Tension by Drop Weight Method under Constant Flow Rate

An equipment measuring dynamic interfacial tension was established,which can measure dynamic interfacial tension over 0.5mN/m with the surface age above 0.05s. Photocell was also used to set up a counter of drops in this equipment.The movement of the drop,the circulation current in the drop will have some influence in the break away process.An equation for calculating dynamics surface tension was proposed based on force balance considering the above factors.Experimental data were used to obtain the equation of the reel attire velocity of movement U0.The results of calculation for oil-water systems show that the equation was suitable for dynamic drop weight technique with relative error below 0.5%. The dynamic interfacial tension of organic liquids-water solutions of SDS,CTAB,TritionX-100 were calculated by above equations.The surface excess and diffusion coefficients of various surfactants were estimated.It shows above equations available in common use.