Graphene quantum resistive sensing skin for the detection of alteration biomarkers

Abstract

International audienc

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

“…With respect to equation (2), Fick derived a second law for one-dimensional diffusion in isotropic substances, i.e. in the x direction, 13,60 which is given by equation…”

“…The vapor diffusion will proceed through the membrane up to a state of equilibrium provided that the concentration balance constitutes the driving force. 13,60 Classically the diffusion coefficient value D can be calculated by following the integral`time lag' method on the basis of the mathematical description made by Fick's law, which explains an analogy between the heat and mass flows in a polymer, based on the free chain mobility. 61 The transfer of a substance through a polymer matrix is thus proportional to the concentration …”

“…At the beginning of the test, a 0.3-cm 3 of VOC was injected in the bottom half of the vessel and vapor gets distributed with equal pressure throughout the chamber sealed with the test membrane. 13 The diffusion time of analytes through the QRS transducer is evaluated to a fraction of second, which is assumed to be negligible compared with the diffusion time through the membrane of several seconds. All the experiments were performed at 258C and were repeated thrice at each operating condition for reproducibility.…”

“…vapors of toluene allowed the determination of transport parameters through nanocomposite films with thè time lag' approach. 13 In contrast, by using the diffusion coefficient values, the effective average aspect ratio of fillers could also be calculated. …”

“…In this context, the use of quantum resistive sensors (QRS) made of conductive polymer nanocomposites (CPCs) developed in our group [13][14][15] appeared to be a good alternative to existing methods of determination of the diffusion coefficient, as it was found to combine rapidity, convenience in use, and reliability. 16 The low amount of solvent required for the analysis (only a few cubic centimeters) is really remarkable.…”