Ariel University Center of Samaria, Physics Department, Ariel, Israel.
J Colloid Interface Sci. 2012 Oct 15;384(1):157-61. doi: 10.1016/j.jcis.2012.06.023. Epub 2012 Jun 27.
The formation of liquid marbles was studied in the situation where hydrophobic particles coating the marbles "come from air". Droplets of water/ethanol solutions of various concentrations were coated with three kinds of powders: polytetrafluoroethylene, polyvinylidene fluoride and polyethylene. We established that there exists a critical concentration of ethanol, and correspondingly a critical surface tension of the water/ethanol solution allowing formation of liquid marbles. A critical surface tension depends on the kind of the powder. In parallel, wetting transitions of water/ethanol solutions were studied on the layers of the same polymer powders. The onset of wetting transitions on the powders took place at the concentrations of ethanol coinciding with those enabling the formation of liquid marbles. Wetting transitions stipulate the formation of liquid marbles when a droplet is deposited on a layer of hydrophobic powder. This assumption was validated by the experiments performed with di-iodomethane and glycerol.
研究了在疏水粒子从空气中“附着到液珠上”的情况下液珠的形成。将水/乙醇溶液的液滴用三种粉末：聚四氟乙烯、聚偏二氟乙烯和聚乙烯进行涂覆。我们确定存在一个临界乙醇浓度，以及相应的能够形成液珠的水/乙醇溶液的临界表面张力。临界表面张力取决于粉末的种类。同时，还在相同聚合物粉末层上研究了水/乙醇溶液的润湿转变。在与形成液珠的浓度相吻合的乙醇浓度下，在粉末上开始发生润湿转变。当液滴沉积在疏水性粉末层上时，润湿转变会促使液珠的形成。这一假设通过用二碘甲烷和甘油进行的实验得到了验证。
