Microfluidic – Internal coating

In complex, frequently miniaturized and specialized fluidic systems, great demands are made on the inner surfaces which are in contact with other media. Atmospheric pressure plasma processes enable the controlled adjustment of surface characteristics. Hereby, products like disposables can be equipped with sophisticated features cost-effectively within seconds of treatment time.

In fluidic systems made from dielectric materials, such as glass or plastics, cold plasmas can be generated at atmospheric pressure allowing an all-over coating of the inner channels. For the coating, the channel or tube is placed between two electrodes. Electric fields which excel the ignition field strength in the channel are generated with AC voltage. Applying an adequate gas or gas mixture streaming through the channels, inner surfaces can be coated or activated in a post processing. By using local electrodes, hydrophobic stops can be refined in hydrophilic channels, amongst other things.

A local inner coating allows the separation of liquid multiphase systems using the specific surface tensions of the different phases. Corresponding separators need small channel dimensions or membrane structures, so that the individual liquid phases can get in contact with different surfaces. The phases can be separated by guiding the multiphase system through a channel structure which splits into hydrophobic and hydrophilic channels. The following applies: The better the channel structures are constructed and dimensioned, e.g. regarding surface, volume and aspect ratio, in view to the fluid segment diameter, viz. the droplets, the more complete the separation can be achieved. In combining micro structuring techniques and surface coating processes, such separating systems can be realized with a wide range of materials.  


  • All-over coating of surfaces in tubes and capped channels
  • Realization of fluidic functions, such as "hydrophobic stop" and fluidic separation
  • Possibilities to use more cheaper materials, for example plastics instead of glass
  • Seal surfaces of microfluidic systems stay uncoated

Our offer

  • Hydrophobic and hydrophilic coatings
  • Coatidropletngs for -based microfluidics, fluidic separators and hydrophobic stops
  • Consulting and prototype production
  • Chemically reactive coatings for the coupling of oligomers or biomolecules
  • Analytics, function tests, process and plant development