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    Electro spray Electro spinning Company

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    Head Office in Málaga

    C.\ Estados Unidos S/N. 29738 Rincón de la Victoria (Málaga). Spain

    Request a Quote

    Looking for a quality and affordable Company with a deep know-how and expertise in Microfluidics Techniques?

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    Phone us

    +0034 639 756 903

    Working Hours

    Monday - Thursday: 09:00 to 18:00
    Friday: 09:00 to 15:00
    Saturday - Sunday: Closed

    • svg
    • svg
    • svg

    Head Office in Málaga

    C.\ Estados Unidos S/N. 29738 Rincón de la Victoria (Málaga). Spain

    Request a Quote

    Looking for a quality and affordable Company with a deep know-how and expertise in Microfluidics Techniques?

    * Please Fill Required Fields *
    img

    Phone us

    +0034 639 756 903

    Working Hours

    Monday - Thursday: 09:00 to 18:00
    Friday: 09:00 to 15:00
    Saturday - Sunday: Closed

    Coaxial CoFlowing Tech.

    DESCRIPTION

    CoFlowing consists of using the drag of a moving fluid on a meniscus from another fluid which is immiscible with the drag and is injected through a capillary tube. Depending on the conditions (liquids properties, geometry of tubes,…) monodisperse microspheres, microcapsules or microfibers significantly lower than that of the fluid injected hole diameters can be obtained.
    Picture that shows how the outer liquid drags to the inner, which breaks into micro-droplets.

    When the inner and outer flow rates are low for both fluids a system of dripping is produced just at the end of the injection tube (droplets are typically generated periodically).

    However with the higher liquid flow outside the inner fluid is more stretched into long filaments or jets liquids (jetting mode) that due to varicose instabilities breaks into droplets. In the jetting mode two regimes can be identified: the narrowing regime, in which the filament diameter decreases axially, and the widening regime, in which the filament diameter increases axially. Narrowing jets are formed when viscous forces acting on the jet surface due to the outer jet, the drag liquid, overcomes the forces of confinement due to surface tension , where the inertia of the inner fluid is negligible. In these situations, the jet narrowing occurs due to the inner speed is higher than the outer speed. On the other hand, widening jets are produced when the forces due to the inertia of the inner flow exceed confinement forces due to surface tension. By contrast, the internal fluid flows faster than the outside, which is responsible for producing a slow jet widening thereof.
    Including another outer coaxial channel it is possible to generate fibered or spherical microcapsules in the nanometric range. This technique is called Coaxial CoFlowing.
    Another approach of production of droplets, particles and capsules in the micron range is Confined Selective Withdrawal, a technique developed in Doxa® S.D. that uses a setup very similar to Coaxial Co-Flowing. It also uses a Core Fluid, a Shell Fluid and the Focusing Liquid (drags and focuses the capsules) to the end of the tip.
    Sketch of Selective Withdrawal setup.

    SCOPE

    Doxa offers its customers access to this technology for basic or applied research, but also to integrate it in their own labs. To achieve this we employ the latest equipment that allow the fabrication of microfluidics devices.
    • Puller (stretching of capillars to desired diameter)
    • Microforge (cutting of capillary tips to desired diameter).
    • Molds and negative templates for the manufacture of printed circuit in PDMS.
    • Mixer for preparation of PDMS solution.
    Details of capillary tips of glass prepared in Doxa Lab.

    FEATURES

    The control of the geometry and the flow rate per each channel for the fluids flowing coaxially enables a full control of the process. Typical diameter sizes range from dozens of microns to 500 microns.

    Coflow enables the production of high monodisperse droplets or bubbles, iIt is ensured a low dispersion of the size of droplets. The control on the process allows the encapsulation of liquids with good control on the characteristics of the structure of the capsule (shell´s thickness and morphology).

    Scientific Papers

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      C. N. Baroud, F. Gallaire, and R. Dagla.
      Dynamics of microfluidic droplets.
      Lab Chip. 10: 2032-2045, 2010.

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      E. Castro-Hernández, V. Gundabala, A. Fernández-Nieves, J.M. Gordillo.
      Scaling the drop size in coflow experiments.
      New Journal of Physics. 11, 2009.

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      Vilanova, N. and Gundabala, V.R. and Fernandez-Nieves, A.
      Drop size control in electro-coflow.
      Applied Physics Letters. 99(2), 2011.

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      Vilanova, N. and Gundabala, V.R. and Fernandez-Nieves, A.
      Drop size control in electro-coflow.
      Applied Physics Letters. 99(2), 2011.

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      Utada, A.S. and Fernandez-Nieves, A. and Stone, H.A. and Weitz, D.A.
      Dripping to jetting transitions in coflowing liquid streams.
      Physical Review Letters. 99(9), 2007.