Air-channel fabrication for microelectromechanical systems via sacrificial photosensitive polycarbonates

This research involves the fabrication of encapsulated air-channels via acid-catalyzed degradation of photosensitive polycarbonates (PCs). There is a need for lower-temperature, degradable polymeric materials to fabricate buried air-channels for microelectromechanical systems (MEMS), microfluidic devices, and micro-reactors. Some polycarbonates undergo thermolytic degradation in the temperature range of 200 to 350 degreesC. These polycarbonates are also known to undergo acid-catalyzed decomposition in the presence of catalytic amounts of acid. A small percentage of an acid in the polycarbonate formulation can greatly reduce the onset of decomposition temperature to the 100 to 180 degreesC temperature range. The photoacid and thermalacid induced degradation behavior of PCs and its use as a sacrificial material for the formation of air-gaps have been studied in this work. The decomposition of several polycarbonates with the aid of in situ generated photo-acid has been demonstrated and applied to the fabrication of micro air-channels. Based on FT-IR, mass spectrometry, and thermogravimetric analysis (TGA), a degradation mechanism was proposed.