Fast Mass Transport Through Sub-2-Nanometer Carbon Nanotubes

• Published in: Science (American Association for the Advancement of Science) Vol. 312; no. 5776; pp. 1034 - 1037
• Main Authors: Holt, Jason K, Park, Hyung Gyu, Wang, Yinmin, Stadermann, Michael, Artyukhin, Alexander B, Grigoropoulos, Costas P, Noy, Aleksandr, Bakajin, Olgica
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 19.05.2006; The American Association for the Advancement of Science
• Subjects: Carbon; Carbon nanotubes; Cross-disciplinary physics: materials science; rheology; Density; Exact sciences and technology; Flow velocity; Flows in ducts, channels, nozzles, and conduits; Fluid dynamics; Fundamental areas of phenomenology (including applications); Gases; Materials science; Membranes; Modeling; Nanoscale materials and structures: fabrication and characterization; Nanotubes; P branes; Permeability; Physics; Polycarbonates; Silicon nitrides; String theory; Water; Water flow; Carbon nanotubes; Liquid flow; Gas flow; Mass transfer; Flow measurement; Molecular dynamics method
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1126298

We report gas and water flow measurements through microfabricated membranes in which aligned carbon nanotubes with diameters of less than 2 nanometers serve as pores. The measured gas flow exceeds predictions of the Knudsen diffusion model by more than an order of magnitude. The measured water flow exceeds values calculated from continuum hydrodynamics models by more than three orders of magnitude and is comparable to flow rates extrapolated from molecular dynamics simulations. The gas and water permeabilities of these nanotube-based membranes are several orders of magnitude higher than those of commercial polycarbonate membranes, despite having pore sizes an order of magnitude smaller. These membranes enable fundamental studies of mass transport in confined environments, as well as more energy-efficient nanoscale filtration.