Analysing the properties of a thermoformed polyimide film for a gas chromatography valve

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This proposal seeks NSERC funds to address a current problem of APN-AFP inc., in Québec, namely developing high quality valves for chromatography. In the recent years, an unusual high rejection rate was observed not continuously, and the diaphragm of the valves, microfabricated in polyimide was identified as the element causing a so high rejection rate, that can reach 50% in some periods of the year. In a context of high productivity, due to the high demand, this can compromise the efficiency of the company, and create a work surcharge. The fabrication of such diaphragm includes a series of multi-step hot embossing processes demanding control of parameters such temperature, compression charges, and others. The team of APN-AFP inc. optimised the process over the last months, but without reaching significant results. The hypotheses behind this project is that the parameters of temperature, air humidity, process loads, and storing the diaphragm sensitively affect the intrinsically microstructure of the polyimide diaphragm. By an innovative approach unexplored up to now, in 6 months, we plan to carry out a parametric study combining mechanical processing, advanced spectroscopy, mechanical testing, differential scanning microscopy, and advanced surface analyses to assess which are the element responsible to induce changes so important to compromise the performances of the diaphragm. This is expected to improve the competitiveness of APN-AFP inc., and by extension all the Canadian manufacturing industry of high-added value ultra-precise products. We propose to mainly investigate a route towards systematic characterization through advanced chemical and mechanical technique of all the steps required to produce the diaphragm from polyimide raw material. This is not a routine work, mainly because the literature is unclear of the precise role that temperature, humidity and fabrication processes can affect polyimide structure. APN-AFP inc. from its side, needs to push the materials to work at the highest performance limits. By this work, intrinsically, we are pushing the knowledge of the polyimide structure/property relationships over the frontier of the known.