Abstract ID: NSPMR_117

Electric Fields Turn the Tide: Paper-Based Device Harnesses Voltage

to Tame Fluid Instabilities
Shubhonil Sarkar1,3, Rohit Kumar2, Sania Arora2, Rohit Dhiman2, Niloy De2,3, Sampad Laha3, Suman Chakraborty3
1Department
of Chemical Engineering, National Institute of Technology Agartala, Tripura, India
2Departmentof Chemical Engineering, National Institute of Technology Hamirpur, Himachal Pradesh, India
3Department of Mechanical Engineering, India Institute of Technology Kharagpur, West Bengal, India

Motivation & Introduction Materials & Methods

(a) • Base material: Whatman filter paper. • Resident phase: Pure anhydrous glycerol.
• Viscous fingering is a classical interfacial
instability driven by differences in viscosity • Support: Glass slides. • Invading phase: 1% w/v Rhodamine B
during displacement flow in porous or confined dye + 100 nM KCl solution
• Electrodes: Graphite, silver wires.
domains [1], [2].
Electrode Drawing Sensor Assembly Paper-based Sensor
• It limits efficiency in key areas like oil recovery,
contaminant removal, and microfluidics.
• Prior studies on electrokinetic stabilization: (b)
immiscible systems and Hele-Shaw geometries.
Graphite Shading Glue Gun
• Objective of our research: To study the (HB Pencil)

combined effect of capillary force and the

applied electric field on the interfacial instability (+ve)

during miscible phase mixing in porous media. + Central

Electrode

• Supplement and validate experimental data with Figure 1: Viscous fingering in Hele-Shaw Non-conducting Top
Front View Back View
machine learning–based image analysis for cell with a planar channel geometry (a) (Shaded Paper Strip) (Shaded Paper Strip)
glue (-ve) Outer Electrode

real-time pattern classification and diagnostics. and, radial geometry (b). Adapted from [3].
Figure 2: Schematics of (a) electrode drawing, (b) sensor assembly, and (c) paper-based device.

Results & Discussion

Figure 3: Experimental Setup Snapshots from Experiments Observations

Initial Intermediate Steady State • Low voltages enhanced fluid

spreading and induced distinct
0 kV

fingering patterns due to

electrohydrodynamic instabilities.
• Higher voltages increased the
Greyscale
Greyscale
images
image

spreading rate and enlarged the area

covered by the invading fluid, driven
by stronger electrohydrodynamic
0 sec 3 sec 6 sec 16 sec 26 sec 60 sec
effects.
0.5 kV
Greyscale
images

0 sec 2 sec 6 sec 8 sec 14 sec 24 sec

Experimental Procedure Image based analysis workflow

1 Droplet Deposition: 10 µL Rhodamine B - KCl solution
added at device center.
Video of the Frame extraction Cropping of the Applying image
2 Resident Phase Setup: Glycerol pre-applied to introduce a masking
sample from the video image
viscous background.

3 Electric Field Application: DC sourcemeter applied voltage

across electrodes.

4 Imaging Protocol: Spreading recorded via DSLR with Greyscale images Greyscaling the
Display of Sample-to-model
consistent lighting. result image comparison as model weights masked images

5 Image Processing: Binary conversion, masking, and edge

detection for analysis.

Conclusion Acknowledgement
• Applying an electric field increases the spread and instability of dye in porous paper, with We gratefully acknowledge the Dept. of Mechanical Engineering at IIT Kharagpur and Dept.
higher voltage causing faster and wider dispersion. of Chemical Engineering at NIT Hamirpur for providing the essential laboratory facilities, as
well as financial and logistical support, which made this research possible. We also extend
• Characteristic viscous fingering patterns are enhanced at low voltages due to the our sincere thanks to InterPore Chapter India for providing a platform to showcase our work
combined effects of capillarity and electric forces. to the broader scientific community. We deeply value the continuous encouragement,
technical insight, and mentorship provided by our faculty members, whose guidance played
• The experimental setup using paper-based microfluidic devices allows direct observation a pivotal role throughout the execution and development of this study.
and control of interfacial instabilities relevant to practical applications.
References
• High-Throughput Analysis: With ML techniques, large numbers of spreading experiments
1. T. Gao, M. Mirzadeh, P. Bai, K. M. Conforti, and M. Z. Bazant, “Active control of viscous fingering using
can be rapidly processed, supporting comprehensive statistical comparisons across
electric fields,” Nat. Commun., vol. 10, no. 1, p. 4002, Sep. 2019, doi: 10.1038/s41467-019-11939-7.
variables such as applied voltage, geometry, and fluid composition.
2. M. Mirzadeh and M. Z. Bazant, “Electrokinetic Control of Viscous Fingering,” Phys. Rev. Lett., vol. 119,
no. 17, p. 174501, Oct. 2017, doi: 10.1103/PhysRevLett.119.174501.
• AI/ML image analysis enables rapid, unbiased classification of flow patterns, ensuring
accurate comparison between new and previous experimental data. 3. Cvetkovic, I., & Milicev, S. (2024), Advances in Physics X, 9(1).

National Symposium on Porous Media Research 2025