CHARACTERIZATION OF LIQUID CRYSTAL FLOW IN MICROFLUIDIC CHANNELS

Date

2024-12-26

Author

İlhan, Gülce

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Liquid crystals (LCs) are delicate phases of liquid matter possessing molecular order and unique optical properties. LCs were recently shown to be successful in sensor applications towards small to macromolecular-sized analytes due to the sensitivity of their interfaces. Traditional stagnant LC systems, though promising for sensing purposes, have limited adaptability in continuous and automated applications. The microfluidic platform presented herein enables successful stabilization of flowing nematic LC in contact with aqueous phases. We investigated the structural transitions in the flowing LC phase confined in microfluidic channels with tunable, responsive, soft LC-aqueous interfaces. The applied bulk and interfacial shear had direct effects on the director configurations on LC-aqueous interfaces that were stable both for co-current and counter-current flow configurations. Mechanical stresses created at the vicinity of the aqueous interfaces strongly influence the director profiles and topology depending on the bulk nematic director, the orthogonality of the interfacial anchoring condition, and the direction of shear. The findings presented in this thesis lay the groundwork for advanced LC-based autonomous sensing systems, with potential applications in dynamic, high-throughput analysis and complex LC phase behaviors. The developed platform holds promise for next-generation flow-based LC devices, enhancing control over interfacial dynamics for responsive sensor technologies.

Subject Keywords

Liquid Crystals, Microfluidics, Shear, Soft Interfaces, Topology

URI

https://hdl.handle.net/11511/113034

Collections

Graduate School of Natural and Applied Sciences, Thesis