Experimental, Theoretical, and Numerical Investigation of the Electric Field and Surface Wettability Effects on the Penetration Length in Capillary Flow

Abstract

This study addressed the dynamics of capillary-driven flow for different surface wettabilities by concentrating on the influence of electric potential. The capillary flow dynamics were investigated by varying the wettability (plasma-treated, hydrophobic, hydrophilic, and superhydrophilic) of a capillary surface, and the applied electric potential to the liquid ranged from 0 to 500 V. When an electric potential was applied to the liquid, the fluid flow penetration length increased by 30−50% due to the electrohydrodynamic (EHD)-driven flow by the Maxwell (electric) pressure gradient effect. The results showed that the EHD effect enhanced the fluid penetration through narrow gaps. The maximum fluid penetration was attained for every surface at 500 V, particularly for the superhydrophilic surface, which exhibited the highest value. The combined effect of the electric field and wettability resulted in an enhanced fluid penetration speed, reducing the underfill time. In addition, theoretical and numerical models were developed for comparison with the experimental results. The proposed models reinforce the observed fluid flow phenomenon on various surfaces under the influence of an electric field. These findings can provide alternative strategies for controlling the dynamic features of capillary imbibition by introducing an electric field and wettability effects, which has practical implications in flip-chip packaging, microfluidic devices, and the manipulation of biocells.

Electric field and viscous fluid polarity effects on capillary-driven flow dynamics between parallel plates

“…Fig. 4 shows a comparison of the experimental and numerical simulation results with the theoretical model [ 19 ] for different viscous fluids at different voltages (0 and 500 V). The experimentally observed values of the viscosity, surface tension, voltages, nozzle height from the substrate, and length of parallel plates are presented in Table 1 , Table 2 and employed in the comparison of the experimental results with those of the numerical simulation and theoretical model.…”

“…Hence, a complete filling of the chip-to-substrate standoff and shortening of the filling time have been regarded as technical challenges [ 9 , 10 ] in capillary-driven flow. Various studies have claimed that capillary-driven flow can be enhanced by modifying the surface wettability [ [11] , [12] , [13] , [14] ], driving pressure gradient [ 15 ], thermal stresses [ [16] , [17] , [18] ], and electric field effects [ [19] , [20] , [21] , [22] ].…”

Experimental and numerical study of solder bumps impact on the underfill fluid flow under electrohydrodynamic effect

“…This study encompassed both experimental and numerical approaches, albeit without considering the presence of solder bumps. Subsequently, we refined the model by integrating electric field effects [40,41]. Drawing upon this discovery, it can be inferred that the application of an electric field has the potential to expedite underfill fluid flow, particularly in scenarios involving solder bumps.…”