Simplified and direct microchannels fabrication at wafer scale with negative and positive photopolymerizable polydimethylsiloxanes

We report here positive and negative photosensitive polydimethylsiloxanes allowing direct micropatterning on wafer scale. One is a negative photodefinable polydimethylsiloxane (N-photoPDMS) which is covalently bonded on silicon dioxide surfaces, reaching a limit resolution of 20 mu m. The other is an improvement to positive photodefinable polydimethylsiloxane (P-photoPDMS), reaching a limit resolution of 60 mu m. These two novel methods present advantages compared to classical microfabrication methods as they are low cost and are conceived for rapid prototyping on wafer scale. Hence, to show that photoPDMS-based techniques can be applied to the fabrication of complex microfluidic devices used in MEMS or lab-on-chips, 192 N-photoPDMS-based microchannels (20 mu m width) are placed on interdigitated nanoelectrodes (46 nm width) devices (IND), on wafer scale. We present the mechanical properties after crosslinking of N-photoPDMS. We also perform some pressure tests in one microfluidic device to demonstrate the robustness of the photoPDMS-based methodologies.