title: Liquid crystal microfluidics for tunable flow shaping.
abstract: We explore the flow of a nematic liquid crystal in microfluidic channels with a rectangular cross section through experiments and numerical modeling. The flow profile and the liquid crystal orientational profile show three distinct regimes of weak, medium, and strong flow as the driving pressure is varied. These are identified by comparing polarizing optical microscopy experiments and numerical solutions of the nematofluidic equations of motion. The relative stability of the regimes is related to the de Gennes characteristic shear-flow lengths e(1) and e(2), together with the channel's aspect ratio w/d. Finally, we show that the liquid crystalline microfluidic flow can be fully steered from left to right of a simple microchannel by applying transverse temperature gradients.
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany.
authors.forename: Anupam
authors.initials: A
authors.lastname: Sengupta
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany and Center of Excellence NAMASTE, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: Uroš
authors.initials: U
authors.lastname: Tkalec
authors.affiliation: Center of Excellence NAMASTE, Jamova 39, 1000 Ljubljana, Slovenia and Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom and Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
authors.forename: Miha
authors.initials: M
authors.lastname: Ravnik
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Yeomans
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Bahr
authors.affiliation: Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Herminghaus
mesh_terms: D050866:Liquid Crystals / Q000737:chemistry*; D044085:Microfluidics / Q000379:methods*