Ultrasound transmission through monodisperse 2D microfoams

Abstract

While the acoustic properties of solid foams have been abundantly characterized, sound propagation in liquid foams remains poorly understood. Recent studies have investigated the transmission of ultrasound through threedimensional polydisperse liquid foams (Pierre et al., 2013(Pierre et al., , 2014(Pierre et al., , 2017. However, further progress requires to characterize the acoustic response of better controlled foam structures. In this work, we study experimentally the transmission of ultrasounds through a single layer of monodisperse bubbles generated by microfluidics techniques. In such a material, we show that the sound velocity is only sensitive to the gas phase. Nevertheless, the structure of the liquid network has to be taken into account through a transfer parameter analogous to the one in a layer of porous material. Finally, we observe that the attenuation cannot be explained by thermal dissipation alone, but is compatible with viscous dissipation in the gas pores of the monolayer. arXiv:1901.06357v1 [cond-mat.soft]

Microfluidics Mediated Production of Foams for Biomedical Applications

“…As an example, in the automotive industry where foams are used to prevent injuries, they can be exposed to quasi-static and dynamic compression loading, to determine their energy absorption characteristics and impact behavior [128]. For sound insulation, acoustic properties can also be measured using ultrasound transmission [129]. If we look at the biomedical field, the main topic of this review, the use of foams for dermatology requires the investigation of the bubble size, the texture, the stability, and the rheological properties [13].…”

The Acoustics of Liquid Foams

“…In particular, further progress relies on the development of highly controlled foam structures. For instance, regarding polydispersity issues, the transmission of ultrasound through a single layer of monodisperse bubbles (generated by microfluidics techniques) has been recently investigated [75]. In such a material, it was shown that the sound velocity is only sensitive to the gas phase.…”