Hii !
I am Niladri, currently a PhD Student associated with Ashis Research Group at IIT Madras. I work on drop impact dynamics, surface acoustic waves and liquid interaction, extreme wettability surfaces and everything in between. I am also interested in working with biological cells, active matter and their behavior under various impulses. Please feel free to explore the website and contact me for research discussions.
Email: piyushsatpathi962@gmail.com
Please find CV here
Effects of surface acoustic waves on droplet impact dynamics
Surface acoustic waves (SAW) propagating along a solid surface can significantly affect the dynamics of droplet impact. Although droplet impact in presence of SAW has been attempted recently, here, we investigate the effects of surface wettability, droplet size, impact velocity, and SAW power on the impact and spreading dynamics along with post-impact oscillation dynamics of a drop......
Publication : N S Satpathi, K N Nampoothiri, A K Sen, "Effects of surface acoustic waves on droplet impact dynamics", Journal of Colloid and Interface Science (JCIS) 2023,
Drop impact on a superhydrophilic spot surrounded by a superhydrophobic surface
The spatial variation in the wettability of a surface can have a significant effect on the spreading and retraction behavior of an impacting droplet and hence the overall impact dynamics. Although composite surfaces have proven applications, there is a lack of understanding of droplet impact on surfaces with a sudden jump in wettability. Here, we study the behavior of a liquid drop impacting a composite surface having a superhydrophilic (SHL) spot surrounded by a superhydrophobic (SHB) region.......
Publication : N S Satpathi, L Malik, R A Samy, A K Sen, "Drop impact on a superhydrophilic spot surrounded by a superhydrophobic surface", Langmuir 2021,
Surface acoustic wave-based generation and transfer of droplets onto wettable substrates
Fluid manipulation using surface acoustic waves (SAW) has been utilized as a promising technique in the field of microfluidics due to its numerous advantages, over other active techniques, such as low power requirement, facile fabrication methods, and non-invasive nature. Even though SAW-based generation of micron-sized droplets through atomization has been studied, the role of substrate wettability on the characteristics of the transferred droplets has not been explored to date.......
Publication : K N Nampoothiri, N S Satpathi, A K Sen, "Surface acoustic wave-based generation and transfer of droplets onto wettable substrates", RSC Advances 2022,
Deicing of Sessile Droplets Using Surface Acoustic Waves
Deicing has significant relevance in various applications such as transportation, energy production, and telecommunication. The use of surface acoustic waves (SAWs) is an attractive option for deicing as it offers several advantages such as localized heating, in situ control, low power, and system integration for highly efficient deicing. Here, we report an understanding of the dynamics of deicing of microlitre volume water droplets (1 to 30 μL) exposed to low power (0.3 W) SAW actuation using an interdigitated electrode on a piezoelectric (LiNbO3) substrate. We study the time variation of the volume of liquid water from the onset of SAW actuation to complete deicing, which takes 2.5 to 35 s depending on the droplet volume. The deicing phenomenon is attributed to acoustothermal heating which is found to be greatly influenced by the loss of ice adhesion with the substrate and the acoustic streaming within the liquid............
Publication : K N Nampoothiri, A Nath, N S Satpathi, A K Sen, "Deicing of Sessile Droplets Using Surface Acoustic Waves", Langmuir 2023,
Elastocapillary interaction between a long rectangular membrane and a liquid drop
We report elastocapillary interaction between a long rectangular membrane fixed along its central axis and a liquid drop dispensed at one of its ends. The introduction of the drop results in the elastocapillary-driven wrapping of the membrane along its width and a concomitant flow in the resulting conduit along its length. Depending upon the drop size (d) and capillary length scale (Lc), we identified general criteria for achieving complete wrapping of the membrane in the dry state from energy considerations. For small droplets satisfying d ≲ Lc, we find that the critical membrane length (Wc) required for complete wrapping is proportional to the elastocapillary length scale (Lec). In the case of large droplets with d > Lc, the wrapping behavior depends on the ratio of membrane width to elastocapillary length scale (W/Lec) and the ratio of capillary length scale to the elastocapillary length scale (Lc/Lec)........
Publication : R A Samy, N S Satpathi, A K Sen, "Elastocapillary interaction between a long rectangular membrane and a liquid drop", Soft Matter 2021
Buckling and snapping of a thin polymeric membrane exposed to a solvent drop
We report the behavior of a thin and flat rectangular polymeric membrane, fixed at both ends, in contact with a solvent droplet. Depending on the solvent type and volume, and membrane thickness, three different regimes—no buckling, buckling, and snapping—are observed. Our study reveals that the behavior depends on the solubility parameter of the solvent and the ratio of the sum of swelling-induced force and capillary force to the elastic restoring force, ie, the force ratio.......
Publication : R A Samy, N S Satpathi, A K Sen, "Buckling and snapping of a thin polymeric membrane exposed to a solvent drop", Europhysics Letters (EPL) 2020
Link : https://iopscience.iop.org/article/10.1209/0295-5075/132/44001/meta
PDMS membrane-based flexible bi-layer microfluidic device for blood oxygenation
We report the fabrication and experimental study of a flexible bi-layer microfluidic device for blood oxygenation, mimicking the thin alveolar exchange barrier constituting a lung. A facile technique is employed to fabricate the device by sandwiching a thin polymeric membrane as the gas exchange layer between two flexible microchannels. A numerical model coupling the mass, momentum, and species transport equations, is used to simulate oxygen diffusion between the blood and oxygen channels across the gas exchange membrane........
Publication : G Narendran, S Z Hoque, N S Satpathi, K N Nampoothiri, A K Sen "PDMS membrane-based flexible bi-layer microfluidic device for blood oxygenation", Journal of Micromechanics and Microengineering (JMM) 2022
Link : https://iopscience.iop.org/article/10.1088/1361-6439/ac7ea6/meta