In-situ polymerized polyaniline films

A review of three commonly used classes of chemical sensor technologies as applicable to implementation in portable, handheld field instruments is presented. Solid-state gas and chemical sensors have long been heralded as the solution to a wide variety of portable chemical sensing system applications. However, advances in optical sensing technology have reduced the size of supporting infrastructure to be competitive with their solid-state counterparts. Optical, solid-state, and hybrid arrays of sensors have application for portable instruments, but issues of insufficient selectivity and sensitivity continue to hamper the widespread introduction of these miniaturized sensors for solving chemical sensing problems in environments outside the laboratory. In this article, we evaluate three of the major classes of compact chemical sensors for portable applications: (solid-state) chemiresistors, (solid-state) CHEMFETs, and (optical) surface plasmon resonance sensors (SPR). These sensors are evaluated and reviewed, according to the current state of research, in terms of their ability to operate at low-power, small-size, and relatively low-cost in environments, with numerous interferents and variable ambient conditions.

https://www.uta.edu/rfmems/BMC/0720/Background/Chemical%20Sensors%20for%20Portable,%20Handheld%20Field%20Instruments.pdf

Chemical sensors for portable, handheld field instruments

This paper deals with the preparation of graphene oxide-ferrofluid-cement nanocomposites to evaluate the electromagnetic interference (EMI) shielding effectiveness (SE) in the 8.2-12.4 GHz frequency range. It has been observed that incorporation of graphene oxide (30 wt%) along with an appropriate amount of ferrofluid in the cement matrix leads to a shielding effectiveness of 46 dB (>99% attenuation).The presence of graphene oxide and ferrofluid in the cement leads to strong polarizations and magnetic losses that consequently result in higher shielding effectiveness compared to pristine cement. The resulting nanocomposites have shown Shore hardness of 54 and dc conductivity of 10.40 S cm( - 1). SEM reveals the homogeneous dispersion of graphene oxide and ferrofluid in the cement matrix.

https://iopscience.iop.org/article/10.1088/0957-4484/22/46/465701/pdf

Graphene oxide/ferrofluid/cement composites for electromagnetic interference shielding application

Dielectric behavior of polyaniline synthesized by different techniques

TSDC spectroscopy of relaxational and interfacial phenomena.

Electrical conductivity, magnetic susceptibility, and electron-spin-resonance studies are reported in polyaniline and its derivatives poly(o-toluidine), poly(o-ethylaniline), and poly(o-propylaniline). It is shown that substituents on the ${\mathrm{C}}_{6}$ rings of the polymer backbone lead to decreased conductivity, decreased Pauli susceptibility, and an increased number of Curie spins. Also reflecting these features are electron-spin-resonance line shapes, which transform from Lorentzian for polyaniline toward Gaussian for poly(o-propylaniline). These results are interpreted in terms of increased electron localization caused by increased interchain disorder. Furthermore, evidence of electron-electron correlations is presented for poly(o-propylaniline).

N.J. Pinto

Papers

Charge transport and electron localization in polyaniline derivatives.

Dielectric constant and ac conductivity in polyaniline derivatives

Charge transport and electron localization in alkyl ring-substituted polyanilines

Dependence of the conducting state of polyaniline films on moisture