These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
2 files

Microfluidics of Binary Liquid Mixtures with Temperature-Dependent Miscibility

revised on 20.09.2019, 15:07 and posted on 23.09.2019, 14:48 by Maximiliano J. Fornerod, Esther Amstad, Stefan Guldin
Liquid-liquid microfluidic systems rely on the intricate control over the fluid properties of either miscible or immiscible mixtures. Herein, we report on the use of partially miscible binary liquid mixtures that lend their microfluidic properties from a highly temperature-sensitive mixing and phase separation behaviour. For a blend composed of the thermotropic liquid crystal 4-Cyano-4'-pentylbiphenyl (5CB) and methanol, mixing at temperatures above the upper critical solution temperature (UCST; 24.4°C) leads to a uniform single phase while partial mixing can be achieved at temperatures below the UCST. Thermally-driven phase separation inside the microfluidic channels results in the spontaneous formation of very regular phase arrangements, namely in droplets, plug, slug and annular flow. We map different flow regimes and relate findings to the role of interfacial tension and viscosity and their temperature dependence. Importantly, different flow regimes can be achieved at constant channel architecture and flow rate by varying the temperature of the blend. A consistent behaviour is observed for a binary liquid mixture with lower critical solution temperature, namely 2,6-lutidine and water. This temperature-responsive approach to microfluidics is an interesting candidate for multi-stage processes, selective extraction and sensing applications.


EU H2020 grant no 633635 (DIACHEMO)


Email Address of Submitting Author


University College London


United Kingdom

ORCID For Submitting Author


Declaration of Conflict of Interest

No conflict of interest

Version Notes

author version pre-review


Read the published paper

in Molecular Systems Design & Engineering

Logo branding