Self-rolled polymer film: a route to microfluidic devices

International audienceSelf-enrolment is a well-known instability driven by stress inhomogeneity in thin film. Such folding of flat surfaces-which can be previously treated or patterned-into a tube present a great potential of application in microfluidics as the patterning of channel inner surfaces becomes of greater importance for a lot of practical aspects. We investigate the case of PDMS-based bilayer. The instability is driven by PDMS swelling in solvent vapors. The second layer-responsible of the inhomogeneity-can be another harder material. We present two different cases where i-the hard layer is another thin film polymer deposited on the pdms and ii-the hard layer is made by the oxidation of the pdms layer itself. This last case is of main interest since it is the way used for soft-lithography. In Figure 1, we report the inner diameter of self-rolled films as a function of the total bilayer thickness: tubes as small as 25$\mu$m are achieved