Sirsendu Sekhar Barman

EDUCATION

Phd from IIT Kharagpur (2021), M.Sc. from IIT Kharagpur (2014), B.Sc. from University of Calcutta

RESEARCH INTERESTS

Computational Fluid Dynamics, Microfluidics, Advanced Numerical Techniques

Scopus Publications

Gel Electrophoresis of a Polarizable Charged Colloid with Hydrophobic Surface
Sirsendu Sekhar Barman, Somnath Bhattacharyya
Springer Proceedings in Mathematics and Statistics, 2025
Solution of linear & nonlinear difference equations
Arpita Sahoo, Sirsendu Sekhar Barman
Aip Conference Proceedings, 2023
Finite ion size and ion permittivity effects on gel electrophoresis of a soft particle
Sirsendu Sekhar Barman, Somnath Bhattacharyya
Colloids and Surfaces A Physicochemical and Engineering Aspects, 2022
Electrokinetic actuation of an uncharged polarizable dielectric droplet in charged hydrogel medium
Sirsendu Sekhar Barman, Somnath Bhattacharyya, Prashanta Dutta
Electrophoresis, 2021
Electrokinetic transport of an uncharged nonconducting microsized liquid droplet in a charged hydrogel medium is studied. Dielectric polarization of the liquid drop under the action of an externally imposed electric field induces a non‐homogeneous charge density at the droplet surface. The interactions of the induced surface charge of the droplet with the immobile charges of the hydrogel medium generates an electric force to the droplet, which actuates the drop through the charged hydrogel medium. A numerical study based on the first principle of electrokinetics is adopted. Dependence of the droplet velocity on its dielectric permittivity, bulk ionic concentration, and immobile charge density of the gel is analyzed. The surface conduction is significant in presence of charged gel, which creates a concentration polarization. The impact of the counterion saturation in the Debye layer due to the dielectric decrement of the medium is addressed. The modified Nernst–Planck equation for ion transport and the Poisson equation for the electric field is considered to take into account the dielectric polarization. A quadrupolar vortex around the uncharged droplet is observed when the gel medium is considered to be uncharged, which is similar to the induced charge electroosmosis around an uncharged dielectric colloid in free‐solution. We find that the induced charge electrokinetic mechanism creates a strong recirculation of liquid within the droplet and the translational velocity of the droplet strongly depends on its size for the dielectric droplet embedded in a charged gel medium.
Impact of charged polarizable core on mobility of a soft particle embedded in a hydrogel medium
Sirsendu Sekhar Barman, Somnath Bhattacharyya, Partha P. Gopmandal, Hiroyuki Ohshima
Colloid and Polymer Science, 2020
Electrophoresis of a soft particle with a charged polarizable core is analyzed theoretically. The soft particle is embedded in an uncharged hydrogel medium. The hydrodynamics in both the gel medium and the soft layer encapsulating the hard core are governed by the Darcy-Brinkman model. We have considered the numerical model based on the conservation principle of mass, momentum, and ion flux, leading to a coupled set of partial differential equations. A simplified approach under the weak field and low charge density consideration is also proposed. The subtle nonlinear effects arising due to the polarization and relaxation of the double layer and the convective transport of counterions induced by the immobile charge of soft layer are elucidated. These nonlinear effects have negligible impact when the bulk ionic concentration becomes high. The simplified model under the weak field consideration is independent of the core dielectric permittivity. However, the numerical model shows a strong dependence on core permittivity when the applied electric field is moderate. We have also addressed the ion partitioning effect when the dielectric permittivity of the soft layer is different from the gel medium. This creates a counterion saturation in the soft layer, and hence an augmentation in the electrophoresis. Graphical Abstract Distribution of counterion concentration and electric field lines around a charged soft particle in hydrogel medium Distribution of counterion concentration and electric field lines around a charged soft particle in hydrogel medium
Effect of temperature-dependent electrostatic parameters on electroosmotic flow with hydrophobic patches
Sirsendu Sekhar Barman, Somnath Bhattacharyya
Springer Proceedings in Mathematics and Statistics, 2020
Microfluidics has broad utilizations in the field of medical science. The architecture of microfluidic devices desires an improved compassionate of the action of flow and heat transfer attributes in micro- or nano-channel. Electroosmosis is one of the main electrokinetic effects. For the hydrophobic surfaces, a slip boundary condition is established. The present study investigates the effect of temperature-dependent electrostatic parameters on electroosmotic flow with hydrophobic patches. The present study comprises the coupled Poisson–Boltzmann equation, the modified Navier–Stokes equations, the modified Nernst–Planck equation, and the modified energy equation. Governing equations with proper boundary conditions are solved numerically through control volume approach over a staggered grid arrangement. The results are expressed in terms of velocity profiles and surface temperature. Also, we have considered average entropy generation, Savg; average Bejan number, Beavg.
Electrokinetic transport of a non-conducting liquid droplet in a polyelectrolyte medium
Sirsendu Sekhar Barman, Somnath Bhattacharyya
Physics of Fluids, 2020
A numerical study on the electrophoresis of a liquid droplet embedded in a polyelectrolyte hydrogel medium is made by considering the full set of governing equations based on the conservation principle. The surface of the droplet is considered to be charged, and the liquid filling the droplet is non-conducting. The dielectric polarization of the non-conducting droplet is also addressed in the present study. The impact of the surface conduction, double layer polarization, and relaxation effects on the electrophoresis of the non-conducting polarizable uniformly charged droplet is elucidated for a wide range of the gel volume charge density, Debye length, and drop viscosity and size. The presence of the gel immobile charge and slip velocity at the droplet surface leads to a stronger surface conduction, which precludes consideration of a simplified model based on the thin-layer assumption. Our numerical solutions at a low ζ—potential corresponding to a droplet of large viscosity, for which surface conduction is negligible—agree well with the existing analytic solutions for a rigid colloid. The strong electroosmotic flow driven by the immobile charges of the gel medium creates a negatively charged drop in the hydrogel medium to translate along the direction of the applied field. Entrapment of the charged drop can be made by regulating the Debye length and volume charge density of the gel. The charged gel medium is found to be efficient in size-based sorting of the liquid drops.A numerical study on the electrophoresis of a liquid droplet embedded in a polyelectrolyte hydrogel medium is made by considering the full set of governing equations based on the conservation principle. The surface of the droplet is considered to be charged, and the liquid filling the droplet is non-conducting. The dielectric polarization of the non-conducting droplet is also addressed in the present study. The impact of the surface conduction, double layer polarization, and relaxation effects on the electrophoresis of the non-conducting polarizable uniformly charged droplet is elucidated for a wide range of the gel volume charge density, Debye length, and drop viscosity and size. The presence of the gel immobile charge and slip velocity at the droplet surface leads to a stronger surface conduction, which precludes consideration of a simplified model based on the thin-layer assumption. Our numerical solutions at a low ζ—potential corresponding to a droplet of large viscosity, for which surface conduction ...