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Characterization of fully inkjet-printed microsieves and of patterns for the mechanical reinforcement of fragile membranes

: Hammerschmidt, J.; Ueberfuhr, P.; Eck, E.-M.; Zeiner, C.; Thalheim, R.; Baumann, R.R.

Society for Imaging Science and Technology -IS&T-:
NIP30, 30th International Conference on Digital Printing Technologies and Digital Fabrication 2014 : Philadelphia, Pennsylvania, September 7 - 11, 2014
Springfield/Va.: IS&T, 2014
ISBN: 978-0-89208-311-4
International Conference on Digital Printing Technologies and Digital Fabrication <30, 2014, Philadelphia/Pa.>
Fraunhofer ENAS ()

Microsieves are "permeable membranes densely interspersed with uniform pores with a thickness smaller than the pore diameter" [1]. They exhibit excellent properties for filtration applications such as high size selectivity and a high flow rate [2]. We report on the further development of already published, inkjet-based approaches to (1) manufacture microsieves [3, 4] and (2) to reinforce microsieves mechanically [1]: (1) With the inkjet technology microsieves with pores in the micrometer range can be manufactured [4]. However, the distribution of the pore diameters is high which is disadvantageous for a precise size selection in filtration applications. In this report the printing processes are improved to obtain microsieves with uniform pores. In addition, the samples are characterized in terms of porosity and achievable flow rates. (2) Microsieves with pore diameters in the nanometer range can be obtained by float-casting [5]. These are extremely thin and fragile. We developed a process to apply patterns for the mechanical reinforcement by inkjet printing [1, 6]. The patterns which were reported are composed of inhomogeneous lines with high deviations in width and thickness [1, 6]. This probably leads to weak spots which diminish the reinforcing effect locally. Therefore the printing process is improved to obtain patterns with homogeneous lines by a liquid-on-pinned printing strategy [7]. Furthermore a tensile test is applied on a non-porous membrane with a pattern for the reinforcement on top.