Topological Microfluidics

This work represents one of the first comprehensive attempts to seamlessly integrate two highly active interdisciplinary domains in soft matter science - microfluidics and liquid crystals (LCs). Motivated by the lack of fundamental experiments, Dr. Sengupta initiated systematic investigation of LC flows at micro scales, gaining new insights that are also suggestive of novel applications. By tailoring the surface anchoring of the LC molecules and the channel dimensions, different topological constraints were controllably introduced within the microfluidic devices. These topological constraints were further manipulated using a flow field, paving the way for Topological Microfluidics. Harnessing topology on a microfluidic platform, as described in this thesis, opens up capabilities beyond the conventional viscous-dominated microfluidics, promising potential applications in targeted delivery and sorting systems, self-assembled motifs, and novel metamaterial fabrications.

Autorentext
Anupam Sengupta is a soft matter physicist at the Max Planck Institute for Dynamics and Self Organization (MPIDS) Göttingen, Germany. Anupam defended his doctoral research on 'Liquid Crystal Microfluidics' in December 2012 with the highest distinction (summa cum laude). His current research interests include transport of complex fluids and their dispersions, patterns on soft substrates and wetting of complex fluids. He is a graduate of the Indian Institute of Technology, Bombay, with a Dual Degree in Mechanical Engineering (Bachelor and Master of Technology). He takes great interest in mentoring young minds and loves to travel, write and play Sitar.

Zusammenfassung
This work represents one of the first comprehensive attempts to seamlessly integrate two highly active interdisciplinary domains in soft matter science microfluidics and liquid crystals (LCs). Motivated by the lack of fundamental experiments, Dr. Sengupta initiated systematic investigation of LC flows at micro scales, gaining new insights that are also suggestive of novel applications. By tailoring the surface anchoring of the LC molecules and the channel dimensions, different topological constraints were controllably introduced within the microfluidic devices. These topological constraints were further manipulated using a flow field, paving the way for Topological Microfluidics. Harnessing topology on a microfluidic platform, as described in this thesis, opens up capabilities beyond the conventional viscous-dominated microfluidics, promising potential applications in targeted delivery and sorting systems, self-assembled motifs, and novel metamaterial fabrications.

Inhalt
Liquid crystal theory.- Materials and experimental methods.- Functionalization of microfluidic devices.- Nematic liquid crystals confined within a microfluidic device: Static case.- Flow of nematic liquid crystals in a microfluidic environment.- Nematic colloids in microfluidic confinement.- Ongoing research.