Study On Particle Transport In Boron Nitride Nanochannels

The research on particle transport in nanochannels can improve the theory of nanofluidics.The research on nanofluidics will promote the development of single molecule detection technology and the application of nanofluidic chips.In this paper,the phenomenon of single-walled carbon nanotubes and ion transport in cylindrical boron nitride nanochannels was studied by molecular dynamics simulation.A four-probe test bench was designed to verify the reliability of the simulation results.A boron nitride nanochannel model was established.The electroosmotic flow in boron nitride nanochannels and the transport of single-walled carbon nanotubes in boron nitride nanochannels were studied by molecular dynamics simulation.The simulation system consists of boron nitride nanochannels,sodium chloride electrolyte solution and single-walled carbon nanotubes.An external electric field is applied in the axial direction of the boron nitride nanochannel,and parameters such as ion current,radial dispersion of ions,and axial velocity of the particles are counted.The study found that:(1)The rate of electroosmotic flow in boron nitride nanochannels increases with the increase of tangential electric field strength.(2)Positive and negative ions can be screened by taking boron nitride nanochannels of different diameters.(3)When the concentration of the solution is the same,when the carbon nanotubes and carbon tubes are not charged,the radial density distribution of sodium ions and chloride ions in the pipeline remains stable,and the radial density of sodium ions forms 0.7 nm from the center of the pipeline.At the peak,the radial density of chloride ions forms a peak at 0.43 nm.When the single-walled carbon nanotubes are positively charged,the difference from the carbon-free tube or the uncharged carbon tube is that the radial density of sodium ions is 0.3 nm.A small peak appears at which the radial density of chloride ions is higher at the center and then decreases.(4)When the charged neutral single-walled carbon nanotubes enter the boron nitride nano-tube,the volume occupied by the single-walled carbon nanotubes will affect the formation of electroosmotic flow,so that the axial movement speed of the ions is reduced,and the blocking current is always less than the reference.Current;when single-walled carbon nanotubes are charged into boron nitride nano-tubes,when the concentration is low,the single-walled carbon nanotubes will attract more counter ions,and the axis of single-walled carbon nanotubes under the action of electric field force The increase of velocity increases the suppression of the axial velocity of the ion occupying position.At this time,the blocking current is greater than the reference current.When the concentration is higher,the influence of the charge on the ion velocity is weakened,and the volume occupancy plays a dominant role.The blocking current is less than the reference current,and the two compete with each other for current crossover.In order to verify the accuracy of the molecular dynamics simulation results,a four-probe test bench was designed and built.The accuracy of the molecular dynamics simulation results was verified by studying the conductance in different concentration solutions.