پارميدا شاه حسيني

Nanofluidic systems have enabled innovative applications in water purification, molecular sensing, an‎d energy storage. However, Joule heating caused by electrical resistance can disrupt the performance of these systems, making the control an‎d reduction of heat dissipation crucial. This study investigates the effect of charge distribution patterns in the soft layer coating the walls of cylindrical nanochannels on Joule heating an‎d key electrohydrodynamic characteristics. These characteristics include ion selec‎tivity, ion current rectification, electroosmotic flow, an‎d viscous dissipation. In this research, three distinct charge distribution patterns in the polyelectrolyte layer were examined: unipolar, bipolar (with varying positive-to-negative charge ratios), an‎d tripolar. To analyze ion transport behavior in each configuration, the governing equations including the Poisson-Nernst-Planck equations with thermal diffusion terms, Navier-Stokes equations, an‎d the energy equation were solved numerically.The results revealed that bipolar nanochannels offer superior thermal management compared to unipolar an‎d tripolar designs. At a concentration ratio of λ_c=100 an‎d an applied voltage of V_app=5 V, the bipolar configuration (523 nW) demonstrated a 22.5% reduction in Joule heating compared to unipolar an‎d tripolar configurations (675 nW). Furthermore, the analysis of electroosmotic flow velocity showed that bipolar nanochannels achieved a maximum speed of 9.83 × 10⁻³ m/s at λ_c=10, a significant improvement over the maximum speeds of 2.39 × 10⁻³ m/s (unipolar) an‎d 2.85 × 10⁻³ m/s (tripolar). This enhanced performance stems from the inherent ability of bipolar nanochannels to modulate internal electric fields an‎d improve ionic mobility. Another notable feature of this configuration is its excellent ionic current rectification capability, making it an ideal can‎didate for constructing ionic transistors an‎d nanofluidic diodes. The findings of this study provide valuable insights for designing efficient nanofluidic membranes in diverse applications.

گرمايش ژول , نانوكانال نرم , لايه پلي الكتروليتي چند قطبي , اتلاف ويسكوزيته , توزيع بار

Joule heating , Soft nanochannels , Multipolar polyelectrolyte layer , Viscosity dissipation , Charge distribution

Parmida Shahhoseini

Prof. Seyed Nezameddin Ashrafizadeh