Plasma treatment of PDMS used in microfluidic devices is used to produce a permanent bond between surfaces and to improve analyse flow within microfluidic channels.
PDMS (Polydimethylsiloxane) is by far the most popular material used in microfluidics research where it is deployed for rapid prototyping with minimal cost. PDMS, however, requires a surface treatment step in order to produce strong, conformal bonds between surfaces. Plasma treatment of PDMS increases exposes silanol groups (-OH) at the surface of the PDMS layers so that they form strong covalent bonds (Si– O–Si) when brought together with glass. These covalent bonds form the basis of a practically inseparable seal between the layers.
Plasma Treatment of PDMS
- Removal of hydrocarbon groups
- Exposure of hydrophilic -OH groups
- Improved bonding to PDMS, PC and glass
- Improve analyte flow
- Possibility of patterned surfaces with alternating hydrophilic/hydrophobic regions
Henniker’s systems are routinely used for plasma surface treatment of PDMS in microfluidic laboratories throughout the world. They can operate with both oxygen and air. A typical process would use air and activation at low power for tens of seconds. The surfaces are brought into immediate contact for the best possible bonding results.
The larger HPT-300 and HPT-500 instruments feature multiple tray-loading options and allow for increased capacity or treatment of larger devices. Each model of HPT plasma treatment system also features a continuously variable power level from 0-100% of full range so that power levels can be set precisely, both at low levels for activation of PDMS and at higher levels for effective cleaning and activation of glass.
We have a detailed application note on the plasma treatment of PDMS, available to read in the knowledge article section below.