Graphene oxide-stimulated acoustic attenuating performance of tungsten based epoxy films

A tungsten/epoxy composite film integrated with graphene oxide (GO) is prepared via a layer-by-layer assembly method, which shows enhanced acoustic attenuating performance compared with a tungsten/epoxy composite film in the absence of GO. The basic structure consists of tungsten/epoxy/GO/epoxy (W/E/GO/E), in which the inner wrapped epoxy acts as a buffer layer to anchor GO nanosheets on W spheres, and the outer wrapped epoxy layer is designed to prevent GO nanosheets peeling off from W spheres. The design was beneficial in guaranteeing the independence and integrity of the W/E/GO/E structure. The structure of the core-shell composites was characterized with Fourier-transform infrared spectra, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The acoustic properties of the films were evaluated by a conventional pulse-echo overlap technique at the frequency of 9 MHz. It was found that the acoustic attenuation of the optimal W/E/GO/E composite films was much higher than those of traditional W films at a band frequency range from 5 MHz to 12 MHz, and 36.58 ± 0.2 dB cm^-1 MHz^-1 was obtained at 9 MHz. The wrapping of GO on the surface of W/E will create a crumpled surface for better mixing with the epoxy matrix due to hydrogen bonding and chemical bonding, leading to the preparation of a high quality composite film with minimal structural defects including bubbles and cracks. The enhanced acoustic absorption property of the composite films was attributed to a synergistic effect among its multicomponents, as well as the contribution of GO's thermoacoustic effect. W/E/GO/E composite films with such excellent attenuation loss properties have promise to be the backing material for ultrasonic transducers.