A laser ultrasound transducer using carbon nanofibers–polydimethylsiloxane composite thin film

Abstract

The photoacoustic effect has been broadly applied to generate high frequency and broadband acoustic waves using lasers. However, the efficient conversion from laser energy to acoustic power is required to generate acoustic waves with high intensity acoustic pressure (>10 MPa). In this study, we demonstrated laser generated high intensity acoustic waves using carbon nanofibers–polydimethylsiloxane (CNFs-PDMS) thin films. The average diameter of the CNFs is 132.7 ± 11.2 nm. The thickness of the CNFs film and the CNFs-PDMS composite film is 24.4 ± 1.43 μm and 57.9 ± 2.80 μm, respectively. The maximum acoustic pressure is 12.15 ± 1.35 MPa using a 4.2 mJ, 532 nm Nd:YAG pulsed laser. The maximum acoustic pressure using the CNFs-PDMS composite was found to be 7.6-fold (17.62 dB) higher than using carbon black PDMS films. Furthermore, the calculated optoacoustic energy conversion efficiency K of the prepared CNFs-PDMS composite thin films is 15.6 × 10−3 Pa/(W/m2), which is significantly higher than carbon black-PDMS thin films and other reported carbon nanomaterials, carbon nanostructures, and metal thin films. The demonstrated laser generated high intensity ultrasound source can be useful in ultrasound imaging and therapy.

Nitrogen-doped carbon nanofibers derived from polyacrylonitrile for use as anode material in sodium-ion batteries

“…During electrospinning, the needle-collector distance and the feed rate were fixed at 15 cm and 0.75 ml min À1 , respectively [14]. The as-spun nanofibers were first stabilized at 250°C for 2 h in air with a heating rate of 5°C min À1 , and then carbonized under a nitrogen atmosphere at 700, 800, and 900°C, respectively, for 2 h with a heating rate of 2°C min À1 .…”

Generation of planar blast waves using carbon nanotubes-poly-dimethylsiloxane optoacoustic transducer

“…It is sustained by Tong et al 5 who modeled the focusing phenomenon by the lens and obtained analytical solutions for several optoacoustic characteristics including the waveform and acoustic field. On the other hand, Hsieh et al 6 showed that such shockwaves can be generated from a plane surface of CNF-PDMS thin films. In this study, we experimentally and theoretically confirm that planar blast waves can be generated from a plane optoacoustic transducer.…”

Spatiotemporal drug delivery using laser-generated-focused ultrasound system

“…Commercial carbon black powders (Carbon black 73116, Acrylicos Vallejo, Barcelona, Catalonia, Spain) were mixed with PDMS solution (Sylgard 184, Dow Corning Corporation, Midland, MI) and coated onto the curved surface as the light absorption and thermoelastic layer [17]. …”