Fluid flow inside nano-channels coated with a polyelectrolyte brush layer (PEL) is dictated by the brush structure and its interaction with the counter-ion dominated electrical double layer (EDL) near the walls of the PEL channel. In this work, we bring out the confluence of spatial permittivity variation, the influence of proximity between ions in charged PEL channels and non-Newtonian constitutive behavior of the fluid towards altering the electrokinetics of power-law fluids as well as their mechanical to electrical energy conversion capabilities. Our estimates are based on considering the fluidic drag experienced by the ions mediated by effective confinement induced by other ions and fluid rheology. For small electrical double layer (EDL) thicknesses (corresponding to high ionic concentrations), the energy conversion efficiency is shown to be higher for shear-thinning fluids, with a crossover in these characteristics for higher EDL thicknesses. Results show that lower bulk to PEL charge density ratio corresponds to higher conversion efficiencies. PEL also dictates ionic drag in that higher PEL thickness corresponds to higher ionic drag. It has been observed that although the electrokinetic parameters such as streaming potential (electrical potential generated across a channel due to a pressure-driven flow) and energy conversion efficiency (based on the ratio of electrical energy harvested to mechanical energy input) are significantly influenced by the fluid and the nanochannel properties, there exists a cross-over EDL thickness for the variation in the conversion efficiency, which is solely dependent on the properties of the nanochannel. The consideration of the ionic confinement effect allows us to have a more realistic estimate of energy conversion efficiency and yields better estimates of critical regimes of operation depending on EDL thickness for optimal efficiency. These results may yield insight towards designing functional nanofluidic devices with biological interfaces.

涂有聚电解质电刷层（PEL）的纳米通道内部的流体流动由电刷结构及其与PEL通道壁附近的反离子为主的双电层（EDL）的相互作用所决定。在这项工作中，我们提出了空间介电常数变化，带电PEL通道中的离子之间的接近性以及流体的非牛顿本构行为对改变幂律流体的电动势及其机械能和电能的影响的融合。转换功能。我们的估算是基于对其他离子和流体流变学引起的有效限制介导的离子所经历的流体阻力的考虑。对于较小的双电层（EDL）厚度（对应于高离子浓度），对于稀疏剪切流体，能量转换效率更高，对于更高的EDL厚度，这些特性存在交叉。结果表明，较低的体积与PEL电荷密度之比对应于较高的转换效率。PEL还指示离子阻力，因为较高的PEL厚度对应于较高的离子阻力。已经观察到，尽管诸如流动电势（由于压力驱动的流动而在通道上产生的电势）和能量转换效率（基于收集的电能与机械能输入之比）的电动参数受到显着影响。在流体和纳米通道特性方面，存在用于转换效率变化的交叉EDL厚度，该厚度仅取决于纳米通道的特性。离子限制效应的考虑使我们能够更现实地估计能量转换效率，并根据EDL厚度获得更好的关键操作方案估计，以获得最佳效率。这些结果可能会为设计具有生物界面的功能性纳米流体装置提供见识。