Translocation of nanoparticles through a polymer brush-modified nanochannel

Abstract

A basic understanding of the transport mechanisms of nanostructures in a polymer brush-modified nanochannel as well as the brush-nanostructure interactions at molecular level is important to design and fabricate emerging smart nano/ microfluidic channels. In this work, we report coarse-grained molecular dynamics simulations of the translocation of nanoparticles through a cylindrical nanochannel coated with the polymer brush. The effects of the interparticle interaction and grafting density on the distribution and electrokinetic transport of nanoparticles are addressed in detail. Analysis of the distribution and velocity profiles of nanoparticles from the simulations indicate that the location of nanoparticles along the radial direction and their migration velocity are very sensitive to the change of interparticle interaction. We find complicated transport dynamics of nanoparticles under the influence of various grafting densities. The nanoparticles show markedly different translocation behavior upon increasing the grafting density, which depends on the counterion distribution, free room within the brush, nanoparticle-polymer friction, and brush configuration. Our results may serve as a useful starting point for the transport of nanostructures in polymer-modified channels and help to guide the design of novel smart nanofluidic channels for controlling the migration behavior of nanostructures. V C 2012 American Institute of Physics.

Electro-kinetic phenomena in porous PET films filled with liquid crystals

“…However, despite a long history of experimental and theoretical investigations devoted to the electrically induced flows in channels and porous materials, [8][9][10][11] a number of problems are not solved up to now. [12,13] For example, there is a lack of information about specific features of such flows arising in non-Newtonian liquids with some degree of an orientational order, like liquid crystals (LCs), showing complicated electro-rheological behaviour. [14][15][16] In the case of nematic liquid crystals (NLCs) with the orientational structure described in terms of the unite vector (director n), shear flows can arise due to intrinsic connection between n and a velocity gradient.…”

Streaming potential and electroviscous effects in soft nanochannels: towards designing more efficient nanofluidic electrochemomechanical energy converters

“…Such a scenario is particularly meaningful given several recent nanouidic applications. [34][35][36] All the previous studies on the subject (see the previous paragraph) had invariably considered non-overlapping EDLs. Finally, we provide for the rst time the effect of the so electrokinetic transport on affecting the corresponding electroviscous effect.…”

“…This explicit quantication of the role of the induced streaming potential on the overall transport has been absent in the previous studies, and becomes extremely relevant in determination of ow strength in so nanochannels. 34 The results from the present calculation are compared with that of a rigid nanochannel having zeta potential identical to the electrostatic potential at the interface of the FCL and the solid substrate (of the so nanochannel). The central ndings of this study are that the streaming potential and electroviscous effects for so nanochannels are markedly different from that of the rigid nanochannels.…”

Adhesion of nanoparticles to polymer brushes studied with the ghost tweezers method

“…21 For larger NPs, the free energy showed a minimum with respect to nanoparticle location, thus indicating a preferential depth of NP immersion into the brush. Cao et al 28 modeled NP diffusion in a cylindrical channel grafted walls using dissipative particle dynamics (DPD) framework with Lennard-Jones quasiparticles. The authors varied the grafting density and the attraction between NPs and tethered chains and observed a transition from static NPs trapped on the chains to fast transport of NPs in the channel center.…”