Focussed flow droplet generator
Microfluidic droplet generators are excellent tools for generating highly reproducible microsized droplets. This way droplets are generated with much higher precision and repeatability compared to conventional methods.
Micronit has more than 15 years of experience of making microfluidic chips such as droplet generators.
By tuning the relative viscosities, surface tension, and velocities between the dispersed and the continuous phase droplets of almost any size can be created. Oil-in-water (O/W) droplets can be generated directly using the glass chips. Water-in-oil droplets (W/O) are best formed in hydrophobic channels (coated glass). This to prevent droplets from sticking to the channel walls. Upon request Micronit can coat chips with an hydrophobic anti-stiction coating.
Two of the standard microfluidic geometries used for the production of droplets are focused flow and ‘T’-junction. Ultimately, the choice of geometry is generally based on the fluids used and the production rates required. A general rule is that for higher flow rates the focused flow geometry tends to provide a more stable droplet formation system than the ‘T’-junction. There are many variables which can affect the size, frequency and consistency of the droplets produced including:
- Channel dimensions and geometry
- Flow actuation stability
- Flow rates of each fluid, both relative and total
- Channel wetting properties: hydrophobic (coated), hydrophilic (uncoated), etc.
- Miscibility of the continuous (outer) and dispersive (inner) fluids
- Viscosity and surface tension of the continuous (outer) and dispersive (inner) fluids
- Surfactant type and concentration