Conductive bio-Polymer nano-Composites (CPC): Chitosan-carbon nanotube transducers assembled via spray layer-by-layer for volatile organic compound sensing

vQRS Based on Hybrids of CNT with PMMA-POSS and PS-POSS Copolymers to Reach the Sub-PPM Detection of Ammonia and Formaldehyde at Room Temperature Despite Moisture

“…By increasing the average gap ΔZ between CNT, the vapour molecules generate tunnelling conduction that yield exponential variations of the global resistance of transducers [23,78], according to Equation (3) When exposed to 2 ppm of formaldehyde vapours PS-CNT and PMMA-CNT vQRS see their responses increasing by 88% and 64%, respectively, by the introduction of POSS, through the substitution of undoped polymer nanocomposites by PS-co-POSS-CNT and PMMA-co-POSS-CNT. The same conclusion can be made when the vQRS are exposed to 3 ppm of ammonia vapour.…”

“…By increasing the average gap ∆Z between CNT, the vapour molecules generate tunnelling conduction that yield exponential variations of the global resistance of transducers [23,78], according to Equation (3), this is why these sensors are called quantum resistive vapour sensors vQRS [21,51]:…”

“…Several works also mention the use of carbon nanotube-based sensors for the detection of ammonia [17][18][19], but CNTs without functionalization have poor chemical selectivity [20] and the resulting conducting architecture tends to have a poor structural stability when assembled without any binder or matrix [21]. This is why several researchers have experimented the functionalization of CNT by insulating polymers, like PMMA [22] chitosan [23], poly(lactic acid) PLA [24], or intrinsically-conducting polymers (ICP), like poly(pyrrole) (PPy) [25][26][27], poly(thiophene) (PEDOT) [27,28], or poly(aniline) (PANI) [27,28], which can lead to a positive synergy. However, it seems that reaching the ppb range of detection makes the use of nanostructured transducers compulsory, as only the few works using this strategy report such a high sensitivity.…”

Gas barrier efficiency of clay- and graphene-poly(isobutylene-co-isoprene) nanocomposite membranes evidenced by a quantum resistive vapor sensor cell

“…Then the nanocomposite solution mixtures were deposition on interdigitated electrodes (IDEs) by the spray layer-by-layer (sLbL) developed in our group, which allows the control of the sensor's hierarchical conducting architecture. [50][51][52][53][54][55][56] The spray conditions were set as follows:…”

“…In previous studies on the quantification of chemo-resistive responses of vQRS in the ppt (parts per thousand) range, [51][52][53][54][55][56] it had been shown that such behavior could be well fitted with the complete Langmuir-Henry Clustering (LHC) model derived from a dual mode sorption law as expressed in equation (6) A…”