Self-healing:A New Skill Unlocked for Ultrasound Transducer

For an ultrasound device, to prolong its lifetime and guarantee the performance is of significant importance. Actually, it is difficult for a traditional piezoelectric ultrasound transducer to recover from physical damage caused by sudden impact, accidental scratches, and fatigue fracture. As a promising ultrasound device, the optoacoustic transducer, the cole part of which is inorganic-polymer nanocomposite, has drawn much attention in recent years. Fortunately, the development of self-healable polymer provides a good chance for us to endow this kind of device with self-healing capability. Here, based on a covalently cured poly(urea-urethane) elastomeric network and carbon nanotubes nanocomposite, we introduce a catalyst-free and room temperature self-healing optoacoustic transducer. Such device is designed to have a three-layered structure——self-healing nanocomposite/PDMS/glass. By taking the advantage of the principle of wave superposition, its laser-generated ultrasound can be enhanced greatly. This novel ultrasound transducer behaves excellent self-healing performance, and it can recover from a cut or laser-induced damage. After 10th self-repairs, its output can still maintain 92.3% of the original sound pressure. With a self-focusing technology, the developed device can produce high intensity ultrasound (29.2 MPa); after a self-healing process, its laser-generated ultrasound can be kept as high as 28.7 MPa, which is comparable to those values reported in previous literatures with the same laser energy input. Most importantly, such high intensity ultrasound can be successfully used for thrombolysis. These promising results demonstrate that the obtained self-healing ultrasound device is suitable for biomedical applications, which may open a new path for smart biomedical device design and fabrication in the future.