Study On The Wettabilities Of Porous Silver

The wetting behaviors is not only an important characteristics of the surface, but also acommon interface phenomenon in nature. It effects the living activity of various animals,plants, also plays an important role in the daily life of human being and the production ofariculture and industry. The wettability of solid depends on the material composition andsurface micro-nano structure. Therefore, the intensive study on the relationship between thewettability and microstructure will promote the development of wetting theory andapplication of solid wetting.The wettabilities of the porous silver is an important reference value for its application inthe field of fluid filtration, electrode materials. This paper prepared the nanoporous silver bydealloying Ag25Zn75alloy with ligament spacings of140,200,250,350,500nm, respectively.and studied the relationships between contact angle and roughness with DI Water dropping onbulk silver,then studied porous silver surface wetting behaviors with DI Water and Glycerin,respectively. The mechanism of the contact angel changing with time was discussed, anddeduced the academic model of contact angel versus time, also, the relations between contactangle and spacing was discussed.Experiments show that, contact angle deceases with increasing roughness with DI Waterdropping on bulk silver; when the specimen is porous silver, the results show that the contactangel decreases slowly for DI Water, and the contact angel falls down quickly at a biggeroriginal angel For Glycerin, then slowly. Studies suggests that, when a droplet fall on thesurface of porous silver, three processes will happen: original contact angle form first, due tothe interfacial energy and the capillary effect of porous structures, etc; Subsequently, thedroplet will spreading because of its gravity and the changing of interfacial energy, etc;Finally, the droplet stop spreading, only permeates into the porous structure. The formula ofcontact angle versus time is where θ0is original angle，?θmisbalance angle，t0is original time，a0stand for the changing speed of angle.The contact angel decreased with increasing ligament spacing up to250nm and thenincreased when the droplet Glycerin.