Microbial Communities:

As part of my postdoctoral research, I investigate the collective motion of bacteria during colonization on interfaces. The community of bacteria responds as an active fluid (e.g. during swarming) or an active solid (e.g. in multicellular biofilm communities) depending on macroscopic environmental conditions. Understanding the growth, adhesion and the interaction of these bacterial communities with surfaces is critically important in many scenarios; for example in halting bacterial growth in implants and medical devices. By using the tools of fluorescence microscopy and hydrodynamic modeling, my interest is towards discovering and quantitatively characterizing the physical, chemical and biological mechanisms that give rise to localized patterns of cell differentiation and gene expression in these living systems. 

Dynamics of spreading microbial swarms and films - bioRxiv preprint
Matrix Production and Sporulation in Bacillus subtilis Biofilms Localize to Propagating Wave Fronts - Biophysical Journal

Instabilities in Thin Viscous Films:

Thin elastic and viscous sheets often give rise to buckling and wrinkling patterns observable in many natural and industrial phenomena. As an everyday example, the wrinkling of the skin in scalded milk and folding of cake batter or honey are driven by bending and stretching deformations in these thin sheets. Motivated by the glass redraw process, I am numerically investigating the stability of thin fluid sheets with spatially varying viscosities under extensional flows, with the goal of further extending this framework to more general constitutive laws.

Wrinkling instability of an inhomogeneously stretched viscous sheet - Physical Review Fluids

Drag Reduction in Laminar and Turbulent Flows:

(with G. H. McKinley and R. E. Cohen)

The papers related to this work from my PhD are listed below:

Exploring plastron stability and fluid friction reduction on robust micro-textured non-wetting surfaces - PhD Thesis
Sustainable drag reduction in turbulent Taylor-Couette flows by depositing sprayable superhydrophobic surfaces - Physical Review Letters
Drag reduction for viscous laminar flow on spray-coated non-wetting surfaces - Soft Matter
High-resolution velocity measurement in the inner part of turbulent boundary layers over super-hydrophobic surfaces - Journal of Fluid Mechanics

Soft Materials:

(with G. H. McKinley and R. E. Cohen)

The fabrication of liquid-repellent surfaces requires the creation of micron or nanometer sized surface textures combined with sufficiently low surface energy coatings. As part of my thesis, I developed a single step spray technique to deposit hydrophobic polymeric microstructures with the ability to tune the ensuing morphology by controlling the fluid jet-breakup. The papers related to the work are listed below:

Solution spraying of poly (methyl methacrylate) blends to fabricate microtextured, superoleophobic surfaces - Polymer
Dispersity and spinnability: Why highly polydisperse polymer solutions are desirable for electrospinning - Polymer

 Biomimetics and Wetting:

(with G. H. McKinley and R. E. Cohen)

Interfacial phenomena manifests in many natural and everyday phenomena. For example, what sets the depth to which aquatic birds dive when hunting for fish? How can we make clothing more resistant to liquid spills? Can we harvest drinking water from air? I have performed both experimental characterization and applied mathematical to address such questions in the papers listed below:

Quantification of feather structure, wettability and resistance to liquid penetration - J. R. Soc. Interface
Optimal design of permeable fiber network structures for fog harvesting - Langmuir
Assessing the accuracy of contact angle measurements for sessile drops on liquid-repellent surfaces - Langmuir
Utilizing dynamic tensiometry to quantify contact angle hysteresis and wetting state transitions on nonwetting surfaces - Langmuir
Designing Robust Hierarchically Textured Oleophobic Fabrics - Langmuir