Barauskas Dovydas, Pelenis Donatas, Vanagas Gailius, Viržonis Darius, Baltrušaitis Jonas
Panevėžys faculty of Technologies and Business, Kaunas University of Technology, Nemuno st. 33-218, Panevėžys 37164, Lithuania.
Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015, USA.
Sensors (Basel). 2019 Jul 23;19(14):3236. doi: 10.3390/s19143236.
A gravimetric gas detection device based on surface functionalized Capacitive Micromachined Ultrasound Transducers (CMUTs) was designed, fabricated and tested for detection of carbon dioxide (CO) and sulfur dioxide (SO) mixtures in nitrogen. The created measurement setup of continuous data collection, integrated with an in-situ Fourier Transform Infrared (FT-IR) spectroscopy, allows for better understanding of the mechanisms and molecular interactions with the sensing layer (methylated poly(ethylene)imine) and its need of surface functionalization for multiple gas detection. During experimentation with CO gases, weak molecular interactions were observed in spectroscopy data. Linear sensor response to frequency shift was observed with CO concentrations ranging from 0.16 vol % to 1 vol %. Moreover, the Raman and FT-IR spectroscopy data showed much stronger SO and the polymer interactions, molecules were bound by stronger forces and irreversibly changed the polymer film properties. However, the sensor change in resonance frequency in the tested region of 1 vol % to 5 vol % SO showed a linear response. This effect changed not only the device resonance frequency but also affected the magnitude of electroacoustic impedance which was used for differentiating the gas mixture of CO, SO, in dry N.
设计、制造并测试了一种基于表面功能化电容式微机械超声换能器（CMUT）的重量法气体检测装置，用于检测氮气中的二氧化碳（CO）和二氧化硫（SO）混合物。所创建的连续数据采集测量装置与原位傅里叶变换红外（FT-IR）光谱仪集成，有助于更好地理解与传感层（甲基化聚（乙烯）亚胺）的作用机制和分子相互作用，以及其对多种气体检测进行表面功能化的需求。在对CO气体进行实验期间，在光谱数据中观察到了微弱的分子相互作用。当CO浓度在0.16体积%至1体积%范围内时，观察到传感器对频率偏移呈线性响应。此外，拉曼光谱和FT-IR光谱数据显示SO与聚合物之间的相互作用要强得多，分子通过更强的力结合在一起，并不可逆地改变了聚合物薄膜的性质。然而，在1体积%至5体积%的SO测试区域内，传感器共振频率的变化呈线性响应。这种效应不仅改变了器件的共振频率，还影响了用于区分干燥氮气中CO、SO气体混合物的电声阻抗的大小。
