Zheng Wenxiu, Sun Chengzhen, Bai Bofeng
State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Polymers (Basel). 2017 Aug 18;9(8):370. doi: 10.3390/polym9080370.
In this paper, a hydroxylated graphite surface is generated as a hydrophilic oleophobic material for the application of oil-water separation, and the effects of hydroxyl density on the three-phase wettability are studied in oil-water-graphite systems. We analyze the adsorption of water molecules on the hydroxylated surfaces and obtain the relationship between water-oil-solid interfacial properties and the hydroxyl density, which results from the synthetic effects of the orientation of molecules and hydrogen bonds. With the increase of hydroxyl density, the water-solid contact angle first decreases rapidly, and then remains constant. The density of the hydrogen bond formed between hydroxyls and water molecules in the adsorption layer can explain the regularity of the three-phase wettability. The orientation of the water molecules in the adsorption layer shows insignificant variation, owing to the hydrogen bond network formed between the water molecules; thus, little change is observed in the hydrogen bond density in the adsorption layer.
本文制备了一种羟基化石墨表面作为用于油水分离的亲水疏油材料，并在油水-石墨体系中研究了羟基密度对三相润湿性的影响。我们分析了水分子在羟基化表面上的吸附情况，并得出了水-油-固界面性质与羟基密度之间的关系，这是分子取向和氢键综合作用的结果。随着羟基密度的增加，水-固接触角首先迅速减小，然后保持恒定。吸附层中羟基与水分子之间形成的氢键密度可以解释三相润湿性的规律。由于水分子之间形成了氢键网络，吸附层中水分子的取向变化不明显；因此，吸附层中的氢键密度变化不大。
