Caltech Postdoc Launch Seminar

Lunch will be served at 11:45AM

Engineering stable and tough colloidal systems

Florence Müller

Rheology modifiers such as colloidal additives are widely used to improve stability and toughness but often add cost and complexity. Beyond raising viscosity, they influence viscoelastic and thixotropic behavior by forming percolated microstructures. Anisotropic or rough particles like fumed silica, sepiolite, and bentonite are especially effective, though they act through distinct mechanisms—anisotropy versus interparticle friction.

This work systematically probes how particle aspect ratio and surface roughness shape colloidal gel networks. A library of model particles with controlled morphology and chemistry was synthesized, enabling thermoreversible gelation and isolating shear history effects. Linking particle-level degrees of freedom to bulk rheology across Mason numbers, we show how anisotropy and topography distinctly tune gel strength, flow, and resilience. These results call for extended descriptors beyond conventional dimensionless numbers and offer design guidelines for next-generation colloidal suspensions.

The 3Cs of the Cell: Centrioles, Centrosomes, and Cilia

Pallavi Panda

Inside every cell, tiny, beautifully organized structures – centrioles - lead a double life as centrosomes and cilia. Together, these microscopic organelles help cells divide, build internal scaffolds, and sense their environment. Despite their size, defects in these structures can lead to developmental disorders, infertility, brain malformations and are often found in many types of cancers.

In this talk, I'll explore what these structures are, how they relate to each other, and why they matter. I'll share insights from my work showing that cells can build centrioles in unexpected ways, sometimes breaking the rules of perfect symmetry yet still getting the job done. It's a story of how even at the smallest scales, life combines precision with creativity.