Microscale tipstreaming in a microfluidic flow focusing device

By S. Anna, H. C. Mayer. 2006

399 citations recorded by the source corpus.

A microfluidic flow-focusing device is used to explore the use of surfactant-mediated tipstreaming to synthesize micrometer-scale and smaller droplets. By controlling the surfactant bulk concentration of a soluble nonionic surfactant in the neighborhood of the critical micelle concentration, along with the capillary number and the ratio of the internal and external flow rates, we observe several distinct modes of droplet breakup. For the most part, droplet breakup in microfluidic devices results in highly monodisperse droplets in the range of tens of micrometers in size. However, we observe a new mode of breakup called “thread formation” that resembles tipstreaming and yields tiny droplets in the range of a few micrometers in size or smaller. In this work, we characterize the growth of the thread and its maximum length as a function of flow variables and surfactant content, and we also characterize the period of droplet breakup as a function of these variables. Our results suggest possible methods for controlling the process. Using a simple flow visualization experiment as the basis, we report on preliminary efforts to model the thread formation process.

Subfields: Biomedical Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/d9b453c8b1b3456ad072487bdc3fb7d8b21680a3

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In Biomedical Engineering

In Electrical and Electronic Engineering

Citations in the corpus

Production of uniform droplets using membrane, microchannel and microfluidic emulsification devices (2012, background): “The droplet size is larger than in dripping regime and can be larger than the orifice size (Anna and Mayer, 2006).”
Formation and manipulation of ferrofluid droplets at a microfluidic T-junction (2010, methodology): “Passive methods generate and manipulate droplets with different channel configurations such as T-junction [8, 9, 10, 11, 12, 13, 14] and flow focusing [15, 16, 17, 18, 19, 20, 21].”
A numerical method for two phase flows with insoluble surfactants (2011, background): “Surfactants can be used to control droplet size when forming emulsions, foams, suspensions, and pharmaceuticals [3].”
A front-tracking method for computation of interfacial flows with soluble surfactants (2008, background): “In particular, surfactants can be used to manipulate drops and bubbles in microchannels [10,23], and to synthesize micron or submicron size monodispersed drops and bubbles for microfluidic applications [2].”