Soft Matter Physics

Nematic liquid crystals and nematic colloids in microfluidic environment. My doctoral research initiated
the systematic integration of two active, interdisciplinary domains of soft matter physics: liquid crystals and microfluidics. Liquid crystals are complex anisotropic fluids, well-known for their display applications. Although the flow of such materials in bulk has been studied for decades, fundamental flow investigations at micro-scales (a millionth of a meter) were not possible due to the lack of appropriate methods to control the initial orientation of the molecules on the channel walls. I have developed experimental tools to overcome this challenge, which has helped to reveal new insights into the physics of complex anisotropic flows, and has demonstrated novel applications beyond the conventional isotropic microfluidics. A feature which is particularly promising for future applications is that topological defects in liquid crystals can serve as effective traps for colloidal particles, aqueous droplets or other microfluidic cargo. By tailoring the boundary conditions and the overall geometry, topological defects in the liquid crystal bulk phase were created at will, and were guided towards a specific target. This is paving the way towards Topological Microfluidics, an emerging discipline in microfluidic science and technology that harnesses the interaction between flow and molecular ordering. In addition to topological patterning, liquid crystal microfluidics was successfully exploited for tuning the fluidic resistance of flow networks. You can find a visual summary of my doctoral research here.

The research was embeddded in the Marie Curie Initial Training Network ’Hierarchy’ and carried out at the Max Planck Institute for Dynamics and Self-Organization, under the supervision of Dr. Christian Bahr and Prof. Dr. Stephan Herminghaus, in active collaboration with Prof. Dr. Jörg Enderlein of the Third Physics Institute, University of Göttingen.


Ongoing Projects
(selected)

Defect-mediated chaotic flows
Dynamics of anisotropic fluid flows with Martin Schoen, Marco M Mazza and Tillmann Stieger
Rheo-optic characterizations of coexisting phases with Jörg Enderlein and Narain Karedla
Pattern formation on soft substrates with Lucas Goehring, and Pawan Nandakishore