Polymer composite microtube array produced by meniscus-guided approach

Single freestanding microtubes of poly(methyl methacrylate)/polypyrrole (PMMA/PPy) are produced based on a meniscus-guided approach. A ring-deposit of nanoparticles is first formed in a meniscus solution of PMMA/PPy nanoparticles by outward liquid flow in fast solvent evaporation. Continuous accumulation of nanoparticles on the ring-deposit is then made by guiding the meniscus upward under the outward flow, thereby forming single composite microtube with controlled outer diameter and wall thickness. The meniscus-guiding enables us to produce an array of freestanding microtubes that are individually controlled in size at the desired positions. We demonstrate individually addressable gas sensors by integrating PMMA/PPy microtubes on electrodes.