Verma Akarsh, Zhang Weiwei, van Duin Adri C T
Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA-16802, USA.
Phys Chem Chem Phys. 2021 May 12;23(18):10822-10834. doi: 10.1039/d1cp00546d.
In this work, the authors have developed a reactive force field (ReaxFF) to investigate the effect of water molecules on the interfacial interactions with vacancy defective hexagonal boron nitride (h-BN) nanosheets by introducing parameters suitable for the B/N/O/H chemistry. Initially, molecular dynamics simulations were performed to validate the structural stability and hydrophobic nature of h-BN nanosheets. The water molecule dissociation mechanism in the vicinity of vacancy defective h-BN nanosheets was investigated, and it was shown that the terminal nitrogen and boron atoms bond with a hydrogen atom and hydroxyl group, respectively. Furthermore, it is predicted that the water molecules arrange themselves in layers when compressed in between two h-BN nanosheets, and the h-BN nanosheet fracture nucleates from the vacancy defect site. Simulations at elevated temperatures were carried out to explore the water molecule trajectory near the functionalized h-BN pores, and it was observed that the intermolecular hydrogen bonds lead to agglomeration of water molecules near these pores when the temperature was lowered to room temperature. The study was extended to observe the effect of pore sizes and temperatures on the contact angle made by a water nanodroplet on h-BN nanosheets, and it was concluded that the contact angle would be less at higher temperatures and larger pore sizes. This study provides important information for the use of h-BN nanosheets in nanodevices for water desalination and underwater applications, as these h-BN nanosheets possess the desired adsorption capability and structural stability.
在这项工作中，作者通过引入适用于硼/氮/氧/氢化学的参数，开发了一种反应力场（ReaxFF），以研究水分子对与空位缺陷六方氮化硼（h-BN）纳米片界面相互作用的影响。最初，进行了分子动力学模拟以验证h-BN纳米片的结构稳定性和疏水性。研究了空位缺陷h-BN纳米片附近的水分子解离机制，结果表明，末端氮原子和硼原子分别与一个氢原子和羟基结合。此外，预测当在两个h-BN纳米片之间压缩时，水分子会分层排列，并且h-BN纳米片的断裂从空位缺陷部位开始。进行了高温模拟以探索功能化h-BN孔附近的水分子轨迹，观察到当温度降至室温时，分子间氢键导致这些孔附近的水分子团聚。该研究扩展到观察孔径和温度对水纳米液滴在h-BN纳米片上形成的接触角的影响，得出的结论是，在较高温度和较大孔径下接触角会更小。这项研究为h-BN纳米片在用于海水淡化和水下应用的纳米器件中的使用提供了重要信息，因为这些h-BN纳米片具有所需的吸附能力和结构稳定性。
