Functional poly(urethane-imide)s containing Lewis bases for SO₂ detection by Love surface acoustic wave gas micro-sensors

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• 作者：Isma?l Ben Youssef ; Halima Alem ; Fr¨¦d¨¦ric Sarry ; Omar Elmazria ; Rafael Jimenez Rioboo ; Carole Arnal-H¨¦rault ; Anne Jonqui¨¨res
• 关键词：Functional polymers ; Tertiary amines ; SAW gas sensors ; Sulfur dioxide
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：185
• 期：Complete
• 页码：309-320
• 全文大小：2359 K

文摘

Functional polymers containing Lewis bases are known as promising materials for the elaboration of highly sensitive micro-sensors for acid gas detection. In this work, poly(urethane-imide)s (PUIs) with Lewis bases were synthesized in two steps only from various functional diols (N-methyldiethanolamine, N-tert-butyldiethanolamine, N-phenyldiethanolamine and 1,4-diethanolpiperazine) containing one or two tertiary amine groups with different chemical structures. The synthesis led to high yields, high molecular weights and a good control of the PUI amine content. These good film-forming polymers were then used as SO₂ sensitive coatings on Love surface acoustic wave (L-SAW) micro-sensors. The physical and mechanical properties required for an optimal micro-sensor design were determined by High Resolution Brillouin Spectroscopy of PUI thin layers. Three-layer micro-sensors were developed by respecting the conditions for the L-SAW generation. The three-layer structure included Quartz ST-90 as the piezoelectric substrate, a ZnO guiding layer and a PUI sensitive layer. These micro-sensors were weakly sensitive to temperature and thus compatible with the targeted application. The experimental results for SO₂ detection showed that all the PUI coatings greatly improved the sensitivity compared to a micro-sensor without polymer coating. The basicity of the amine groups was not determining for the micro-sensor sensitivity to the SO₂ acid gas and the key factor was their steric hindrance. Finally, the micro-sensor sensitivity increased with the accessibility of the amine groups in the order Piperazine-diol < tBu-DEA ? Ph-DEA ? MDEA.