Volatile organic compounds (VOC) sensing has received tremendous attention due to its potential for on-time detection of and prevention of diseases. Thus, developing highly sensitive, selective, and low-cost chemical sensors that can detect trace amounts of VOCs is essential for environmental sustainability and human health monitoring. Here, a synergistic approach combining 3D printing and solution-based deposition techniques is used to pattern 1D and 2D nanoparticles. The carbon nanofibers and MXene flakes were deposited onto the substrate with microchannels via layer-by-layer solution deposition. The nanoparticles trapped by microchannels experiences microfluidic forces, which lead to site-specific deposition and alignment of nanoparticles. The fabricated polymer/nanoparticle composite film benefited from the synergy between two mechanisms: (i) aligned film of nanoparticles for effective charge transfer and (ii) 3D printed polymer microchannels for trapping of VOC molecules that facilitate their diffusion to active sites. As a result, the devices showed improved VOC sensing performance for well-organized and aligned nanofibers/flakes than randomly dispersed nanoparticles. The highly enhanced sensitivity and selectivity were attributed to efficient electron transport and hopping between inter-and intra-nanofiber/flakes along the alignment direction of fibers/flakes. Thus, the polymer/CNF and the polymer/MXene composite devices demonstrated high sensitivity, the low theoretical limit of detection (sub-ppm), high signal to noise ratio (in thousands), fast response (&lt;30 sec), and quick recovery (&lt; 10 s), and a wide sensing range (tens to hundreds of ppm) at room temperature. In addition to its relatively high electrical properties benefiting the chemical sensitivity, the polymer/CNF/MXene composite is compact, lightweight, and mechanically stiff, resulting in the structural stability desired for emerging applications, such as disease diagnosis, agricultural production, environmental monitoring, and food industry.

Nanolayered polymer/nanoparticle composites for volatile sensors

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.