Akdeniz Burak, Wood Jeffery A, Lammertink Rob G H
Soft Matter, Fluidics and Interfaces, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands.
Langmuir. 2024 Mar 19;40(11):5934-5944. doi: 10.1021/acs.langmuir.3c03916. Epub 2024 Mar 7.
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.
扩散泳，即粒子在溶质浓度梯度作用下的移动，在许多应用中具有实际意义，如粒子分选、聚焦和传感。对于电解质溶液中的扩散泳，粒子速度由电解质相对浓度梯度和粒子的扩散泳迁移率描述。电解质浓度通常会在整个系统中随空间和时间变化，它也会随空间和时间影响粒子的zeta电位。这种变化会影响扩散泳行为，尤其是当zeta电位高度依赖于电解质浓度时。在这项工作中，我们表明在微粒表面吸附一层（或四层）聚电解质对（聚二烯丙基二甲基氯化铵/聚苯乙烯磺酸钠）会导致在整个盐浓度实验范围内，相对于盐浓度，zeta电位值有效恒定。这使得扩散泳传输的恒定电位模型能够描述实验观察结果，而在相同电解质系统中未包覆的粒子则并非如此。这项工作突出了使用简单的聚电解质对来调节zeta电位并保持恒定值，以精确控制扩散泳传输。
