太赫兹波调控纳米水通道内水分子的动力学特性的理论研究

In this study, a scientific idea based on terahertz technology is proposed to modulate the transport of water molecules. Within carbon nanotubes with a specific aperture, the confined water molecules form a linear hydrogen bond network. Compared with the hydrogen bond network of bulk water, the chemical potential energy of the hydrogen bond network of confined water decreases significantly, while the frequency of the vibration of the hydrogen bond network is in terahertz region. The terahertz wave with specific frequency can avoid the strong absorption window of bulk water, which can specifically modulate the structure of confined water, and then modulate the flow rate of water molecules through the water channel. Compared with the previous reports, this idea has the advantages of long-range, non-intrusive, non-contact and low energy consumption. By means of molecular dynamics simulation, the above assumptions can be theoretically studied and validated. Finally, we hope that the frequency and intensity threshold of terahertz light required to modulate the structure and dynamic properties of confined water can be estimated for the reference of experimenters. Terahertz technology may have matured and applied in other fields, but it is seldom used to regulate water transport. This study is original and exploratory. This research is aimed at the urgent need of high purity water preparation technology innovation in many high-end manufacturing industries, and is expected to provide theoretical support for the development of new technologies.

本研究提出一种基于太赫兹技术调控水分子输运的科学设想：在特定孔径的碳纳米管内部，受限的水分子形成线性的氢键网络，它与体相水的氢键网络相比，化学势能显著降低，而氢键网络振动的频率在太赫兹区，利用特征频率的太赫兹波可以避开体相水对太赫兹波的强吸收窗口，从而特异性地调控受限水的结构，进而调控水分子透过水通道的流速。相比于已有报道，该调控方法具有长程、非侵入、无接触、低能耗的优势。借助分子动力学模拟可以对上述设想进行理论研究和验证，最终估计出调控受限水的结构和动力学性质所需太赫兹光的频率和强度阈值，供实验人员参考。太赫兹技术可能已经成熟应用在其他领域，但是很少用在调控水的输运，本研究设想兼具原创性和探索性。本研究面向众多高精尖制造行业对高纯水制备技术革新的迫切需求，有望为发展新技术提供理论支撑。

纳米水通道内水分子的结构和动力学特性决定着纳米水通道的功能，研究人员从纳米水通道的化学修饰和结构塑造方面考虑着进一步改进纳米水通道对水的渗透性，然而是否存在一种物理手段能够长程、非侵入、无接触、低能耗地调控水通道内水的结构和动力学行为？这引发了项目负责人的思考。本项目提出一种基于太赫兹技术调控水分子输运的科学设想：在特定孔径的碳纳米管内部，受限的水分子形成线性的氢键网络，它与体相水的氢键网络相比，化学势能显著降低，而氢键网络振动的频率在太赫兹区，利用特征频率的太赫兹波可以避开体相水对太赫兹波的强吸收窗口，从而特异性地调控受限水的结构，进而调控水分子透过水通道的流速。研究发现特定频率的太赫兹波在特定强度下，能够引起水通道内水分子的渗透相变和结构相变，基于定量研究，研究估计出调控受限水的结构和动力学性质所需太赫兹光的频率和强度阈值，以供实验人员参考。在项目的资助下共发表高水平学术论文14篇。本研究面向众多高精尖制造行业对高效水输运的膜和设备的制备技术革新的迫切需求，有望为发展新技术提供理论支撑。