Abstract
Microfabrication of high-aspect-ratio polymeric microstructures via deep X-ray lithography traditionally involves either crosslinking or scissioning a polymer film spun-cast on a substrate. A post-exposure development procedure is usually employed to remove the unwanted polymer, leaving behind lithographically patterned structures. Instead, we use a novel synthesis technique wherein polymerization of a mixture of monomers in solvent is initiated, through a mask, with hard X-rays. The resulting polymer precipitates out of the solvent, thus limiting the spatial propagation of the reaction only to the exposed regions. Such a technique offers a unique way for the patterned synthesis of polymers from a variety of monomer-solvent systems. Here, we present the first results on the synthesis of high-aspect-ratio microstructures of a thermoreversible hydrogel, poly (N-isopropylacrylamide), and an ionic hydrogel, poly (methacrylic acid). These stand-alone, implantable microstructures are envisioned to be potentially useful in such diverse areas as biosensors, microactuators, controlled release applications, and cell and tissue engineering.
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This paper was first presented at the High Aspect Ratio Microstructures (HARMST) 2003 conference in Monterey California, June 2003.
We would like to thank Dr. Francesco De Carlo (APS) for his discussions on beamline simulations. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Basic Energy Sciences (BES), Office of Science, under contract number W-31-109-ENG-38.
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Tirumala, V., Divan, R., Mancini, D. et al. Fabrication of high-aspect-ratio hydrogel microstructures. Microsyst Technol 11, 347–352 (2005). https://doi.org/10.1007/s00542-004-0453-9
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DOI: https://doi.org/10.1007/s00542-004-0453-9