Theoretical assessment of wettability on silane coatings: from hydrophilic to hydrophobic
Theoretical assessment of wettability on silane coatings: from hydrophilic to hydrophobic
复制标题
硅烷涂层润湿性的理论评估：从亲水性到疏水性
DOI：
10.1039/c9cp01232j
复制
发表时间：
2019-04-28
影响因子：
3.3
通讯作者：
Wang, Liming
中科院分区：
文献类型：
--
作者：
Huang, Haiming;Wang, Weiliang;Wang, Liming
用第一性原理量子力学计算方法研究了不同类型硅烷修饰的石墨烯表面的势分布和功函数，建立了其表面疏水性等级。发现功函数依赖于硅烷上原子的电负性。通过电子密度差揭示了硅烷与石墨烯表面相互作用的局域化特征。功函数被证明是理解表面极化率和表面润湿性质的一个临界量。通过使用水作为探针流体进行接触角的实验测量，不同硅烷接枝的表面显示出疏水性的变化，这与通过功函数计算得到的表面极化率的趋势相反。与功函数相关的接触角可以用线性方程来拟合。
The potential distribution and work function of a graphene surface modified by various types of silanes are investigated by first principles quantum mechanical calculations to establish its surface hydrophobicity hierarchy. It is found that the work function relies on the electronegativity of atoms on silane. The localization feature of interaction between silane and the graphene surface is demonstrated by the electron density difference. The work function is demonstrated to be a critical quantity in understanding the surface polarizability and thereby the surface wetting properties. By performing contact angle measurements experimentally using water as the probe fluid, surfaces grafted with different silanes show hydrophobicity variation that is found to follow the reverse trend to that of the proposed surface polarizability obtained through the work function calculation. The work function-dependent contact angle can be fitted with a linear equation.