Wang, H, Khodaparast, S, Carroll, J et al. (3 more authors) (2020) A microfluidic-multiwell platform for rapid phase mapping of surfactant solutions. Review of Scientific Instruments, 91 (4). 045109. ISSN 0034-6748
Abstract
Measurement of the phase behavior and (meta)stability of liquid formulations, including surfactant solutions, is required for the understanding of mixture thermodynamics, as well as their practical utilization. We report a microfluidic platform with a stepped temperature profile, imposed by a dual Peltier module, connected to an automated multiwell plate injector and optical setup, for rapid solution phase mapping. The measurement protocol is defined by the temperature step ΔT ≡ T1 − T2 (≲100 ○C), volumetric flow rate Q ≡ ΔV/Δt (≲50 μl/min), which implicitly set the thermal gradient ΔT/Δt (≃0.1–50 ○C/min), and measurement time (which must exceed the intrinsic timescale of the relevant phase transformation). Furthermore, U-shaped microchannels can assess the reversibility of such transformations, yielding a facile measurement of the metastable zone width of the phase diagram. By contrast with traditional approaches, the platform precisely controls the cooling and heating rates by tuning the flow rate, and the absolute temperature excursion by the hot and cold thermal profile, which remain stationary during operation, thus allowing the sequential and reproducible screening of large sample arrays. As a model system, we examined the transition from the micellar (L1) to the liquid crystalline lamellar phase (Lα), upon cooling, of aqueous solutions of sodium linear alkylbenzene sulfonate, a biodegradable anionic surfactant extensively employed in industry. Our findings are validated with quiescent optical microscopy and small angle neutron scattering data.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 Author(s). This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Review of Scientific Instruments, 91 (4). 045109, and may be found at https://doi.org/10.1063/1.5144770 for published article abstract. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Engineering Thermofluids, Surfaces & Interfaces (iETSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Apr 2020 13:51 |
Last Modified: | 29 Apr 2020 13:51 |
Status: | Published |
Publisher: | AIP Publishing |
Identification Number: | 10.1063/1.5144770 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:159972 |