Investigation of AC Electrical Properties of MXene-PCL Nanocomposites for Application in Small and Medium Power Generation

The paper examined Ti3C2Tx MXene (T—OH, Cl or F), which is prepared by etching a layered ternary carbide Ti3AlC2 (312 MAX-phase) precursor and deposited on a polycaprolactone (PCL) electrospun membrane (MXene-PCL nanocomposite). X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) indicates that the obtained material is pure Ti3C2 MXene. SEM of the PCL-MXene composite demonstrate random Ti3C2 distribution over the nanoporous membrane. Results of capacitance, inductance, and phase shift angle studies of the MXene-PCL nanocomposite are presented. It was found that the frequency dependence of the capacitance exhibited a clear sharp minima in the frequency range of 50 Hz to over 104 Hz. The frequency dependence of the inductance shows sharp maxima, the position of which exactly coincides with the position of the minima for the capacitance, which indicates the occurrence of parallel resonances. Current conduction occurs by electron tunneling between nanoparticles. In the frequency range from about 104 Hz to about 105 Hz, there is a broad minimum on the inductance relationship. The position of this minimum coincides exactly with the position of the maximum of the phase shift angle—its amplitude is close to 90°. The real value of the inductance of the nanocomposite layer was determined to be about 1 H. It was found that the average value of the distance over which the electron tunnels was determined with some approximation to be about 5.7 nm and the expected value of the relaxation time to be τM ≈ 3 × 10−5 s.

Formation of Nanostructures on the Solid Surface

Forming nanostructures on the solids surface is one of the promising nanotechnological processes. It has been established that changes in the atomic structure of the solid surface due to the nanostructures formation result both in a significant change in various physical properties of the surface, and in an increase in its durability, strength, hardness, wear resistance. There are many different methods for forming nanostructures on solid surfaces: surface modification with nano-elements (nanoparticles, fullerenes and fullerites, graphene and nanotubes), formation of a nanocomposite layer on the surface, forming quantum dots and whiskers on the surface, implanting ions into the solid surface, laser surface treatment and other processes. The above processes are very complex and for their optimization require detailed research both by experimental and theoretical methods of mathematical modeling. The aim of this chapter was to provide a comparative review of different methods of forming nanostructures on the solids surface and mathematical modeling of these processes various aspects.

Rapid antifouling nanocomposite coating enables highly sensitive multiplexed electrochemical detection of myocardial infarction and concussion markers

Here we describe an ultra-fast (< 1 min) method for coating electrochemical (EC) sensors with an anti-fouling nanocomposite layer that can be stored at room temperature for months, which provides unprecedented sensitivity and selectivity for diagnostic applications. We leveraged this method to develop a multiplexed diagnostic platform for detection of biomarkers that could potentially be used to triage patients with myocardial infarction and traumatic brain injury using only 15 microliters of blood. Single-digit pg/mL sensitivity was obtained within minutes for all the biomarkers tested in unprocessed human plasma samples and whole blood, which is much faster and at least 50 times more sensitive than traditional ELISA methods, and the signal was stable enough to be measured after one week of storage. The multiplexed EC sensor platform was validated by analyzing 22 patient samples, which demonstrated excellent correlation with reported clinical values.