Thermodynamic Barrier for Nanoparticle Penetration into Nanotubes

Abstract

It is promising yet challenging to develop efficient methods to separate nanoparticles (NPs) with nanochannel devices. Herein, in order to guide and develop the separation method, the thermodynamic mechanism of NP penetration into solvent-filled nanotubes is investigated by using classical density functional theory. The potential of mean force (PMF) is calculated to evaluate the thermodynamic energy barrier for NP penetration into nanotubes. The accuracy of the theory is validated by comparing it with parallel molecular dynamics simulation. By examining the effects of nanotube size, solvent density, and substrate wettability on the PMF, we find that a large tube, a low bulk solvent density, and a solvophilic substrate can boost the NP penetration into nanotubes. In addition, it is found that an hourglass-shaped entrance can effectively improve the NP penetration efficiency compared with a square-shaped entrance. Furthermore, the minimum separation density of NPs in solution is identified, below which the NP penetration into nanotubes requires an additional driving force. Our findings provide fundamental insights into the thermodynamic barrier for NP penetration into nanotubes, which may provide theoretical guidance for separating two components using microfluidics.

Adsorption and Catalytic Activity of Gold Nanoparticles in Mesoporous Silica: Effect of Pore Size and Dispersion Salinity

“…Based on the analysis of our experimental data, we find that the maximum amount of AuNPs adsorbed on m SiO 2 increases nearly by an order of magnitude upon increasing d pore from 4.1 to 15.6 nm. Note that the surface excess is normalized to the surface area, and the observed increase in the adsorbed amount of AuNPs with increasing d pore is due to the reduced geometric barrier for AuNPs penetrating the m SiO 2 matrix. , At d pore comparable to the diameter of the AuNPs, adsorption observed is significantly lowered due to the physical barrier for NPs accessing the pore space. The small amount of AuNPs adsorbed at d pore = 4.1 nm is likely due to the binding of the AuNPs on the m SiO 2 matrix exterior to the pores.…”

Unexpected effect of an empty cavity on water transport through a combined carbon nanotube

“…Water molecules also display the new transport behavior in the disjoint nanochannel [5,[17][18][19]. It is reported that the nanojunction or the hourglass shape influence water transfer properties as well [20][21][22].…”