Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles

Abstract

Diffusiophoresis, the movement of particles under a solute concentration gradient, has practical implications in a number of applications, such as particle sorting, focusing, and sensing. For diffusiophoresis in an electrolyte solution, the particle velocity is described by the electrolyte relative concentration gradient and the diffusiophoretic mobility of the particle. The electrolyte concentration, which typically varies throughout the system in space and time, can also influence the zeta potential of particles in space and time. This variation affects the diffusiophoretic behavior, especially when the zeta potential is highly dependent on the electrolyte concentration. In this work, we show that adsorbing a single bilayer (or 4 bilayers) of a polyelectrolyte pair (PDADMAC/PSS) on the surface of microparticles resulted in effectively constant zeta potential values with respect to salt concentration throughout the experimental range of salt concentrations. This allowed a constant potential model for diffusiophoretic transport to describe the experimental observations, which was not the case for uncoated particles in the same electrolyte system. This work highlights the use of simple polyelectrolyte pairs to tune the zeta potential and maintain constant values for precise control of diffusiophoretic transport.

Cytotoxic Effects of Doxorubicin on Cancer Cells and Macrophages Depend Differently on the Microcarrier Structure

“…Core/shell microparticles consisting of the MBs coated with eight-layer polymer shells (MB(+8L)) and MC consisting of the polymer shell alone (MC(8L)) were obtained by means of layer-by-layer adsorption of oppositely charged polyelectrolytes (the polycation PAH and the polyanion PSS) onto the MB surface [22,23,31]. About 10 8 MBs, dried after the synthesis, were resuspended in 0.5 mL of ultrapure water.…”

Diffusiophoresis of a Charged Soft Sphere in a Charged Spherical Cavity

“…For the diffusiophoresis of a charged particle in an electrolyte solution, the particle-ion interaction is dominated by electrostatics and the range of its electric double layer with a thickness of the order of the Debye screening length [21]. In the past, the diffusiophoretic motion of a hard particle (which is impermeable to ionic fluids) [22,23], a porous particle (which is permeable) [24], and a soft particle (which has a hard core covered by a porous layer) [25][26][27][28] with an arbitrary electric double layer thickness were studied analytically (by assuming a weak applied electrolyte concentration gradient) and experimentally.…”