Abstract:

The spreading of a drop of an insoluble surfactant solution over precursor, which was driven by surfactant concentration gradient and temperature gradient caused by surface non-uniform heating was modeled.The dimensionless evolution equations of the spreading process, including the equation of film thickness and surfactant concentration, were derived on the basis of lubrication theory and calculated by PDECOL program.The effects of temperature gradient and concentration gradient on the spreading process were discussed.The results showed that decreasing Marangoni number, air-liquid interface Biot number and heating number, and increasing surface Peclet number could delay the spreading process.Changing surface Peclet number would lead to the most remarkable difference in surfactant concentration distribution.