Transport of molecules through carbon nanotube channels in aqueous environment: A molecular dynamics study
- PDF / 3,669,741 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 56 Downloads / 176 Views
0899-N03-08.1
Transport of Molecules through Carbon Nanotube Channels in Aqueous Environment: A Molecular Dynamics Study Yongqiang Xue* and Maodu Chen College of Nanoscale Science and Engineering, University at Albany-State University of New York, Albany, New York 12203, USA * E-mail: [email protected]; URL: http://www.albany.edu/~yx152122. ABSTRACT We present molecular dynamics simulation of molecules transporting through carbon nanotubes for applications in engineered flow channels, focusing on the dynamics of molecules spontaneously inserted into the nanotube channel in aqueous environment. The molecules studied include a C60 molecule, a finite segment of carbon nanotube with smaller diameter, and single/double- stranded DNA molecules. We show that in the absence of water solvation, the van der Waals interaction between the molecule and the nanotube wall can induce a rapid spontaneous encapsulation of the molecule inside the nanotube channel. The encapsulation process is strongly impeded for nanotube dissolved in water due to the competition between the van der Waals, hydrophobic and hydrogen bonding interactions in the nanotube/water/molecule complex. Water adsorption inside the nanotube channel plays an important role in determining the dynamics of the spontaneous insertion process. INTRODUCTION Carbon nanotubes (CNTs) have drawn a great deal of attention as model systems for studying fundamental physics, chemistry and materials science associated with nanostructures [1]. From the inception of research on CNTs, they have been exploited extensively as promising candidates for applications in solid state electronic and photonic devices. The recent progress in developing functionalization schemes to impart solubility and chemical and biological functions to these novel materials has opened up an array of exciting opportunities on the “wet” side of CNT science and technology [2,3]. In particular, the investigation of carbon nanotubes as engineered nanoscale flow channels has attracted a lot of attention in nanofluidics and nanobiotechnology for selective transport of water, proton, ion and macromolecules [4]. Nanoscale flow channels for confining and transporting molecules are ubiquitous in biology and chemical and pharmaceutical industries [5,6]. Molecules confined within narrow channels, with channel widths of a few molecular diameters, can exhibit a wide range of physical behavior. Confinement effects are also important for many applications involving the flow, diffusion and selective adsorption of water, aqueous solutions, ions, polymers and biomolecules [6]. Several recent investigations have suggested that carbon nanotubes, with their rigid nonpolar structures, might be exploited as unique transport channels for nanofluidic devices, with the channel occupancy and conductivity tunable by changes in the local channel polarity and solvent conditions [4]. Carbon nanotubes represent a new system far less complex than the biological nanochannels, which are functionally tunable by the chemical functionalizatio
Data Loading...
