Marker patterning: a spatially resolved method for tuning the wettability of PDMS

N. Bodin-Thomazo (1, 2) , F. Malloggi (1) , P. Guenoun (1)

1 LIONS - Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire
2 IGPS - Institut Galien Paris-Sud

Versatile, inexpensive and easy to use, PDMS became a very common material, especially in the field of microfluidics. Intrinsequally hydrophobic, it can be made hydrophilic by the exposure to oxygen plasma. For some applications, wettability patterning of the PDMS surface is needed, in particular for the formation of monodisperse mutliple emulsions. In this work we present an easy and spatially resolved way to tune the wettability of the PDMS. Patterning is achieved without tedious or complicated surface processing by simply drawing the desired pattern onto the PDMS surface using the permanent ink of a marker as a masking layer. The microfluidic device is then exposed to oxygen plasma prior the bonding and flushed with ethanol when bonded. The parts of PDMS which are protected remained hydrophobic whereas unprotected surfaces are oxydized. The process is demonstrated by forming W/O/W emulsions in a controlled manner.

Domains: Material chemistry

N. Bodin-Thomazo, F. Malloggi, P. Guenoun. Marker patterning: a spatially resolved method for tuning the wettability of PDMS. RSC Advances, 2017, 7, pp.46514-46519. ⟨10.1039/c7ra05654k⟩. ⟨cea-01599520⟩