Researchon The Heavy Drop Morphologies On Solid Surfaces

Wetting property is one of the most important characters of surface properties of solid materials and has been attracting widely attention because of its importance in basic science and practical applications.The wetting property is closely related to drop morphology,therefore researching of the drop morphologies on solid surface is a very important and real significant work.In this paper,some issues about the drop morphologies on solid surface,such as the approximate solution of the morphology of a drop on asymmetrical curved surface,the experimental observation of the morphology and adhesion force of liquid bridge between a cylinder and a flat substrate are studied through experiments,simulations and theoretical analysis.Firstly,the behavior of droplets on flat surface and the quasi-static processes of stretching of liquid bridge were simulated by Surface Evolver program,the drop morphologies obtained from simulation were in excellent agreement with the drop morphologies measured by Dataphysics OCA-20 device,it verified that Surface Evolver could describe the stable morphology of a drop on solid surface well and thereby provided data support for the theoretical model.From the Surface Evolver simulation result,we could clearly observe that the drop profiles almost well fitted into a model we built,then a theoretical model of the morphology of a heavy drop on hydrophobic surface was established.By comparing the characteristic parameters of drop morphology(the maximum radius?wetting radius?height)from the theoretical model and simulation result,giving out the available range of the theoretical model.Finally,the morphology and adhesion force of liquid bridge between between cylinder and flat substrates were studied through experiments.The results showed that the adhesion force of liquid bridge varies by different boundary conditions and related with the increase of the distance of the liquid bridge.Under the condition of constant volume of the total liquid bridge and no control of the threephase line,the total adhesion force of smaller liquid bridges is muchlargerthanthatcaused byonebigliquidbridge.