Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

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The water droplet motion processes actuated by applying surface acoustic waves at various RF powers and frequencies were investigated by numerically modelling and compared with experiment. A three-dimensional computational model of a free water droplet streaming on the surface of the substrate have been developed using Finite Element Method (FEM) with Laminar Two-Phase Flow Moving Mesh approach for Navier–Stokes equations which were coupled with Convection Wave equation (CWE) module of the COMSOL Multiphysics. Water droplet motion speeds were experimentally measured and confirmed for water droplets with the volumes of 2 and 5 μl, at SAW frequencies 34 and 58 MHz, and power range 0.1–1.23 W. The effect of frequency on microfluidic performance such as streaming flows and droplet motion has been studied both numerically and experimentally toward developing MEMS devices for future energy sources, e.g., for direct methanol fuel cells, hydrogen energy, as well as for use in a wide variety of chemical, water desalination and purification of other fluids from salts, germs, bacteria, and viruses based on perspective multiphysical effects.

This work presents a detailed comparison of our computer simulation study with our own experiment on coatings of aluminium wires for high-voltage lines and characterization of coatings. Computer modelling, using finite element method (FEM), has shown a significant dependence of a local electric field enhancement factor (β-factor) on the surface hydrophilicity (wettability). Modelling explained that the β-factor from a micro-tip on a high-voltage line can be decreased with dependence from contact angles. It has been shown that highly porous and hygroscopic properties of the modified surface reduce the contact angle of water droplets on the wire and the β-factor from the rough surface due to the dielectric shielding. Newly engineered surfaces allow for control of the contact angle of a water droplet on the wire and also reduce the β-factor, in comparison with an uncoated surface.

Nanometer size hole fabrication in 2d ultrathin films with cluster ion beams AIP Advances 7, 075014 (2017);