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In this paper, we investigate the use of a graphene oxide (GO)-coated planar inductor as a transducer for gas sensing applications in alternating current (AC) mode. The GO is synthesized using the Hummers method and coated as a functional layer on a square-shaped planar inductor with an area of 16 × 16 mm2 printed on a circuit board (PCB). Preliminary finite element analysis showed that the magnetic field around the inductor was tightened and amplified due to the presence of the GO layer. This result was confirmed by electrical measurements using a vector network analyzer (VNA), revealing that the GO led to an increase in the self-inductance due to its paramagnetic character. In fact, for a frequency of 1 MHz, the series resistance increased significantly by 32% compared to the initial value obtained without GO, while the inductance increased only by 0.18%. After CO2 injection, a frequency screen ranging from 1 MHz to 200 MHz demonstrated that the effect of CO2 is more relevant at low frequencies. Hence, measurements show that for 1 MHz, the series inductance and resistance decrease by about 9.33% and 31%, respectively, from their values measured after GO coating. Accordingly, this work highlights the relevance of the GO-coated inductor as a transducer for CO2 detection working in AC regime. [ABSTRACT FROM AUTHOR]

In this work, we present a simple and fast method for elaborating hybrid membranes by growing metal–organic framework crystals inside a polymer solution. The solution thus obtained was casted then annealed at 90°C for 5 h. This method was tested with poly(vinylidene fluoride) (PVDF) as a piezoelectric polymer and the Cu3(BTC)2, BTC = 1,3,5‐benzene tricarboxylate, as a filler. The characterization of the obtained membranes by attenuated total reflectance Fourier transform infrared spectroscopy and X‐ray diffraction showed the presence of the characteristic signatures of Cu3(BTC)2 and the β‐phase of PVDF. Moreover, scanning electron microscopy images reveal that the Cu3(BTC)2 crystallites have grown along the PVDF membranes. The effect of the filler on both thermal and mechanical properties of the membranes was also studied. POLYM. ENG. SCI., 60:464–473, 2020. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Direct DNA sensor based on new nanocomposite materials (Fc-ac-OMPA/MWCNTs) has been investigated. This nanocomposite was formed by combining the redox oligomer “oligo-methoxy-phenyl-acetonitrile” (Fc-ac-OMPA) and the MWCNTs via a simple π-π stacking interaction in the aim to ameliorate the biosensor performance. The redox indicator and the functional groups of the redox oligomer have been used for monitoring the electrochemical behavior and the flexibility for direct covalent attachment of Hepatitis C DNA probe. This nanocomposite shows high performance of DNA hybridization with a detection limit of 0.08 fmol L −1 . Moreover, the biosensor was applied for the detection of pathogenic bacterium such as DNA from Mycobacterium tuberculosis strand. Developed biosensor has been able to detect a single nucleotide polymorphism (SNP)T (TCG/ TTG) which confers resistance of M. tuberculosis to rifampicin drug. [ABSTRACT FROM AUTHOR]