Verma Ashutosh Kumar, Sharma Bharat Bhushan
School of Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
Gati Shakti Vishwavidyalaya, Vadodara, Gujarat 390004, India.
Langmuir. 2024 Sep 12. doi: 10.1021/acs.langmuir.4c02324.
Interfacial dynamics within nanofluidic systems are crucial for applications like water desalination and osmotic energy harvesting. Understanding these dynamics can inform the rational optimization of two-dimensional (2D) materials and devices for such applications. This study explores the wetting behavior of realistic 2D MoS surfaces incorporating vacancies and atomic steps, known as atomic defects. We employ a combined density functional theory (DFT) and molecular dynamics (MD) computational approach to elucidate the influence of atomic defects on the MoS-water interface. DFT calculations are utilized to determine the charge distribution within MoS. Subsequently, free energy calculations are obtained through MD simulations of the MoS-water interface. Our findings underscore the importance of incorporating atomic defects into MoS surfaces for accurate water contact angle (WCA) predictions in nanofluidic simulations, particularly when using Abal et al. force field parameters. However, the force field developed by Liu et al. yielded more accurate results for pristine MoS surfaces. While these parameters provide reliable outcomes for pristine MoS surfaces, their application to surfaces with defects may lead to underestimation of WCA. This highlights the critical need for realistic surface representations in nanofluidic modeling to accurately capture the complex interactions between water and MoS materials.
纳米流体系统中的界面动力学对于水脱盐和渗透能收集等应用至关重要。了解这些动力学可以为这类应用中二维（2D）材料和器件的合理优化提供依据。本研究探讨了包含空位和原子台阶（即原子缺陷）的实际二维MoS表面的润湿性。我们采用密度泛函理论（DFT）和分子动力学（MD）相结合的计算方法来阐明原子缺陷对MoS-水界面的影响。利用DFT计算来确定MoS内的电荷分布。随后，通过对MoS-水界面的MD模拟获得自由能计算结果。我们的研究结果强调了在纳米流体模拟中，为了准确预测水接触角（WCA），将原子缺陷纳入MoS表面的重要性，特别是在使用Abal等人的力场参数时。然而，Liu等人开发的力场对原始MoS表面产生了更准确的结果。虽然这些参数为原始MoS表面提供了可靠的结果，但将它们应用于有缺陷的表面可能会导致WCA的低估。这突出了在纳米流体建模中需要真实的表面表征，以准确捕捉水与MoS材料之间的复杂相互作用。
