Harsh Jain

Research

I study how geometry and mechanics give soft materials their function. Most of my work is experimental, on setups I build myself, and I use simulations alongside experiments to understand what I see.

Shaping soft structures through buckling

Thin sheets and slender rods buckle when they are compressed. Buckling is usually treated as a failure to avoid, but it can also be used to make shapes on demand.

By heating pre-stretched sheets in selected regions, I molded them into target three-dimensional curved structures. In networks of compressed soft rods, buckling can imprint deformations that store a chosen 3D shape and can later be reversed. I have also studied how thin sheets buckle when compressed at fast rates, combining experiments with numerical solutions of the Euler–Bernoulli equations, with a view to damage tolerance and failure.

Particles on driven paths

Using holographic optical tweezers, I trap microscopic particles in a fluid and drive them along one-dimensional paths. At these scales, viscous forces dominate and inertia is negligible.

Deep traps along the path act as gates. I study how the motions of several particles become correlated as they pass through these gates.

Membranes and living machines

At the Simons Centre for the Study of Living Machines, I have started new lines of work with students: measuring the mechanical properties of giant lipid vesicles with micropipette aspiration, studying transport at the interfaces of model DOTAP membranes, and exploring the mechanics of self-replication, including designing and building a kinematic self-replicating machine.

Restoring N95 masks

During the COVID-19 pandemic, I worked on decontaminated N95 masks. Their filtration efficiency depends on electric charge carried by the mask fibres, and we showed how this charge can be restored after decontamination.

In the lab

I build most of my experimental setups from scratch and write the software that runs them.

Holographic optical tweezers

Built around a spatial light modulator, which shapes the laser's wavefront to create several optical traps and move them along programmable paths. Code →

Micropipette aspiration

For measuring the mechanical properties of soft objects such as giant lipid vesicles, by drawing them into a fine glass pipette under controlled suction.

Instrumentation

Custom electronics for sensing, amplification and data acquisition; optical and optoelectronic sensors; instrument control in Python (GPIB), MATLAB and LabVIEW; and parts designed in CAD and 3D printed.

Simulation

Finite-element simulations of highly non-linear soft materials, including self-contact and friction, in the open-source framework SOFA with meshes from GMSH. A MATLAB solver for the fourth-order Euler buckling equations. Computational fluid dynamics for fluid–structure interaction, and structural analysis in HyperMesh and MSC Nastran.

Students I have mentored

Open-source software