Terahertz volatile gas sensing by using polymer microporous membranes.

A compact, inexpensive, low loss, highly sensitive gas sensor is important for various biomedical and industrial applications. However, current gas sensors still have an inadequate study in terahertz (THz) frequency range. In this study, simple multilayer-stacked microporous polymer membranes are experimentally validated in the THz regime for organic vapor sensing under ambient atmosphere and room temperature. The hydrophilic porous polymer structure provides a large surface area to adsorb polar vapors, and exhibits excellent discrimination in different types of organic vapors based on distinct dipole moments. Various concentrations of volatile vapors can also be successfully distinguished by detecting the limits of low ppm concentrations. Furthermore, the microporous structural gas sensor has a reasonable response time in repeat usage. This study would provide new perspectives on toxic gas sensing and exhaled breath detection applications in the THz spectral frequency.