Micro-Electromechanical Acoustic Resonator Coated with Polyethyleneimine Nanofibers for the Detection of Formaldehyde Vapor

Abstract

We demonstrate a promising strategy to combine the micro-electromechanical film bulk acoustic resonator and the nanostructured sensitive fibers for the detection of low-concentration formaldehyde vapor. The polyethyleneimine nanofibers were directly deposited on the resonator surface by a simple electrospinning method. The film bulk acoustic resonator working at 4.4 GHz acted as a sensitive mass loading platform and the three-dimensional structure of nanofibers provided a large specific surface area for vapor adsorption and diffusion. The ultra-small mass change induced by the absorption of formaldehyde molecules onto the amine groups in polyethyleneimine was detected by measuring the frequency downshift of the film bulk acoustic resonator. The proposed sensor exhibits a fast, reversible and linear response towards formaldehyde vapor with an excellent selectivity. The gas sensitivity and the detection limit were 1.216 kHz/ppb and 37 ppb, respectively. The study offers a great potential for developing sensitive, fast-response and portable sensors for the detection of indoor air pollutions.

Integrated sensing layer of bacterial cellulose and polyethyleneimine to achieve high sensitivity of ST-cut quartz surface acoustic wave formaldehyde gas sensor

“…Fig. 7(b) [28,[34][35][36], and there is no report available using the SAW sensor. Table 2 compares the sensitivity, response time and recovery time for the different types of formaldehyde gas sensors in literature.…”

“…It has a wide range of applications in polymer dyes [30], papermaking [31], fiber modification [32] and biomedicine [33]. The PEI molecules contain a large number of amino groups, which have a good selectivity to adsorb the formaldehyde molecules and are suitable for detection of formaldehyde gas [34][35][36].…”

Review of Gravimetric Sensing of Volatile Organic Compounds

“…In response to these challenges, several methods of polymer deposition have been created that increase the overall surface area for more adsorption sites and shorter diffusion lengths. Electrospinning is the most accessible of these methods, and has been used by multiple groups to show excellent sensitivity to VOCs. ,, By using electrospinning to deposit poly­(ethylene oxide) on SAWs, Liu et al were able to decrease response times by over 50% in comparison to solid, thin-film polymer coatings due to the increase in surface area from electrospinning . Matatagui et al were able to use electrospun polyvinylpyrrolidone (PVP) to sense toluene from 50 to 273 ppm .…”

Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS–MEMS Technique

“…Gas sensors that are used to detect hydrogen sulfide [4], carbon dioxide [5], hydrogen [6], nitrogen dioxide [7], and formaldehyde [8] have been miniaturized using microelectromechanical system (MEMS) technology. Gas microsensors that use this technology are quiet and highly sensitive, feature low power consumption, and can be mass-produced easily.…”

“…The oxidation-reduction method is used to synthesize the sensing film, which consists of PPy/RGO. Most gas sensors [6][7][8][9][10][11][12] have a heater to generate the WT for the sensitive film, but this study produced an AGS without a micro-heater. This AGS operates at room temperature, so it is more efficient in terms of power consumption.…”