Enhanced selectivity of a 3D-printed microfluidic gas detector towards different volatile organic compounds (VOCs) for the effective monitoring of indoor air quality in vehicles

Abstract

In the age of connected mobility, monitoring volatile organic compounds (VOCs) inside the vehicle plays a pivotal role in effectively controlling in-cabin air quality conditions. In this context, it is imperative to develop new monitoring devices that not only detect VOCs at low concentrations, but also can discern those compounds that pose a major risk to the health and comfort of occupants. Microfluidic gas detectors have recently emerged as a promising solution for the cost-effective discretization of VOCs in interior environments. Although microfluidic gas detectors may not yet reach the accuracy of other analytical methods, these devices offer a simple and compact design, can work at room-temperature, and do not require a carrier gas to operate; which represent a clear competitive advantage for their implementation in the vehicle. This work intends to study the feasibility of a 3D-printed microfluidic gas detector for the semi-selective detection of VOCs inside the vehicle cabin. In particular, this research aims to analyze whether the selectivity of these devices can be improved by (i) optimizing the thickness of the polymer layer on the walls of the microchannel, and (ii) understanding the influence of the chemical affinity between VOCs and the coating polymer. Empirical results reveal that thicker polymer films enable to enhance and expand the retention capabilities of the microchannel. Additionally, the Hansen solubility parameters are presented as a suitable tool to analyze and determine how polymer-analyte affinity, in combination with other intrinsic properties of analytes, influences the elution of contaminants from the microfluidic channel as well.