Characterization of shapes and volumes of droplets generated in PDMS T-junctions to study nucleation
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Date
2018-10
Publication Type
Journal Article
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Abstract
We characterize shapes and volumes of droplets generated in PDMS T-junctions and assess the use of this type of microfluidic device to generate droplets suitable for the study of nucleation. Water droplets were formed in oil in a PDMS T-junction and subsequently stored. Droplet volume reproducibility and stability were investigated from acquired micrographs. By theoretically analyzing the influence of the mean volume of a population of droplets on the estimation of nucleation rates, we have shown that deviations in mean volumes can seriously affect the estimates, unless such deviation is smaller than 10%. This condition is fulfilled if experiments are repeated using the same microdevice. Measured droplet polydispersity remained low enough to treat the droplets as monodisperse. Immersing the microdevice in a water bath mitigates solvent evaporation, and allows for very accurate temperature control. Finally, a screening procedure was used to select the ideal operating conditions to obtain droplets with the desired sizes. Applying this method in devices with increasing T-junction cross sectional area, we have demonstrated a scaling-up of droplet volumes close to an order of magnitude while tuning the droplet shape, i.e., the average length to width ratio, at values between 1 and 1.2.
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published
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Journal / series
Volume
138
Pages / Article No.
444 - 457
Publisher
Elsevier
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Date collected
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Subject
T-junction; Droplet volume; Droplet shape; Reproducibility; Evaporation; Nucleation
Organisational unit
03348 - Rudolf von Rohr, Philipp (emeritus) / Rudolf von Rohr, Philipp (emeritus)
03484 - Mazzotti, Marco (emeritus) / Mazzotti, Marco (emeritus)
Notes
Funding
146662 - Development of phase change emulsion systems for thermal energy storage (SNF)