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The synthesis of new corrugated layers of graphene is presented and its composite with polyaniline was electrochemically characterized for supercapacitor electrodes.

In this work, a new approach is presented with the aim of showing a simple way of unifying the classical formulas for the forces of the Coulomb’s law of electrostatic interaction <mml:math display="inline"> <mml:mrow> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>C</mml:mi> </mml:msub> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:mrow> </mml:math> and the Newton’s law of universal gravitation <mml:math display="inline"> <mml:mrow> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>G</mml:mi> </mml:msub> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:mrow> </mml:math> . In this approach, these two forces are of the same nature and are ascribed to the interaction between two membranes that oscillate according to different curvature functions with spatial period <mml:math display="inline"> <mml:mrow> <mml:mfrac> <mml:mrow> <mml:mi>ξ</mml:mi> <mml:mi>π</mml:mi> </mml:mrow> <mml:mi>k</mml:mi> </mml:mfrac> </mml:mrow> </mml:math> , where <mml:math display="inline"> <mml:mi>ξ</mml:mi> </mml:math> is a dimensionless parameter and <mml:math display="inline"> <mml:mi>k</mml:mi> </mml:math> is a wave number. Both curvature functions are solutions of the classical wave equation with wavelength given by the de Broglie relation. This new formula still keeps itself as the inverse square law, and it is like <mml:math display="inline"> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>C</mml:mi> </mml:msub> </mml:mrow> </mml:math> when the dimensionless parameter <mml:math display="inline"> <mml:mrow> <mml:mi>ξ</mml:mi> <mml:mo>=</mml:mo> <mml:mn>274</mml:mn> </mml:mrow> </mml:math> and like <mml:math display="inline"> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>G</mml:mi> </mml:msub> </mml:mrow> </mml:math> when <mml:math display="inline"> <mml:mrow> <mml:mi>ξ</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1.14198</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>45</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . It was found that the values of the parameter <mml:math display="inline"> <mml:mi>ξ</mml:mi> </mml:math> quantize the formula from which <mml:math display="inline"> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>C</mml:mi> </mml:msub> </mml:mrow> </mml:math> and <mml:math display="inline"> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>G</mml:mi> </mml:msub> </mml:mrow> </mml:math> are obtained as particular cases.

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P-type and n-type metal oxide semiconductors are widely used in the manufacture of gas sensing materials, due to their excellent electronic, electrical and electrocatalytic properties. Hematite (α-Fe2O3) compound has been reported as a promising material for sensing broad types of gases, due to its affordability, good stability and semiconducting properties. In the present work, the efficient and easy-to-implement sol-gel method has been used to synthesize α-Fe2O3 nanoparticles (NPs). The TGA-DSC characterizations of the precursor gel provided information about the phase transformation temperature and the mass percentage of the hematite NPs. XRD, TEM and XPS data analyses indicated the formation of two iron oxide phases (hematite and magnetite) when the NPs are subjected to thermal treatment at 400 °C. Meanwhile, only the hematite phase was determined for thermal annealing above 500 °C up to 800 °C. Besides, the crystallite size shows an increasing trend with the thermal annealing and no defined morphology. A clear reduction of surface defects, associated with oxygen vacancies was also evidenced when the annealing temperature was increased, resulting in changes on the electrical properties of hematite NPs. Resistive gas-sensing tests were carried out using hematite NPs + glycerin paste, to detect quaternary ammonium compounds. Room-temperature high sensitivity values (Sr ~ 4) have been obtained during the detection of ~1mM quaternary ammonium compounds vapor. The dependence of the sensitivity on the particle size, the mass ratio of NPs with respect to the organic ligand, changes in the dielectric properties, and the electrical conduction mechanism of gas sensing was discussed.

In the original article Chiara Valsecchi's last name was spelled incorrectly. It is correct as reflected here.

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