Department of Mechanical Engineering, State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, 100084, Beijing, China.
Center for Nano and Micro Mechanics, Tsinghua University, 100084, Beijing, China.
Nat Commun. 2023 Apr 21;14(1):2295. doi: 10.1038/s41467-023-37970-3.
The transport of fluid and ions across nanotubes or nanochannels has attracted great attention due to the ultrahigh energy power density and slip length, with applications in water purification, desalination, energy conversion and even ion-based neuromorphic computing. Investigation on individual nanotube or nanochannel is essential in revealing the fundamental mechanism as well as demonstrating the property unambiguously. Surprisingly, while carbon nanotube is the pioneering and one of the most attractive systems for nanofluidics, study on its response and performance under osmotic forcing is lacking. Here, we measure the osmotic energy conversion for individual double-walled carbon nanotube with an inner radius of 2.3 nm. By fabricating a nanofluidic device using photolithography, we find a giant power density (up to 22.5 kW/m) for the transport of KCl, NaCl, and LiCl solutions across the tube. Further experiments show that such an extraordinary performance originates from the ultrahigh slip lengths (up to a few micrometers). Our results suggest that carbon nanotube is a good candidate for not only ultrafast transport, but also osmotic power harvesting under salinity gradients.
由于超高的能量密度和滑移长度，纳米管或纳米通道中的流体和离子传输引起了极大的关注，其在水净化、海水淡化、能量转换，甚至基于离子的类脑计算等方面都有应用。对单个纳米管或纳米通道的研究对于揭示基本机制以及明确展示其性能至关重要。令人惊讶的是，虽然碳纳米管是纳米流体学的先驱者之一，也是最具吸引力的系统之一，但对其在渗透压作用下的响应和性能的研究却很少。在这里，我们测量了具有 2.3nm 内径的单个双壁碳纳米管的渗透压能量转换。通过使用光刻技术制造纳米流体装置，我们发现 KCl、NaCl 和 LiCl 溶液在管内传输时的功率密度高达 22.5kW/m。进一步的实验表明，这种非凡的性能源于超高的滑移长度（高达几微米）。我们的研究结果表明，碳纳米管不仅是超快传输的良好候选者，而且也是在盐度梯度下进行渗透压能量收集的良好候选者。
