Flexible, wearable polymer transducers

In Module 2, we learned that standard ultrasound transducers are made using rigid, synthetic ceramic crystals like PZT housed in a hard plastic casing. While PZT is the industry standard and provides excellent sensitivity, it is also highly brittle and rigid.

But what if we could make a transducer that actually bends and wraps around the patient?

Welcome to the newest breakthrough in transducer design: the flexible polymer transducer!

Construction and Piezoelectric Properties

Scientists are now moving beyond rigid ceramics. Recent innovations in materials science have led to the creation of ultra-flexible ultrasound patches. These new transducers are constructed by integrating porous graphene with 3D-printed piezoelectric polymers.

Are these new flexible patches piezoelectric, or are they like CMUTs? The answer is they are piezoelectric! Because these new materials are made of piezoelectric polymers, they still rely completely on the piezoelectric effect to function. They convert electrical energy into sound energy (the reverse piezoelectric effect) and return echoes back into electrical energy (the direct piezoelectric effect), exactly like traditional PZT. 

The major difference is that they replace the rigid, breakable ceramics with highly flexible, printable polymers.

Advantages and Disadvantages

• Advantages: The absolute biggest advantage is their flexibility! Because they are made from malleable polymers, they can conform directly to the curves of the human body. Furthermore, by using 3D printing and porous graphene, they can be customized in frequency, produce high-quality images, and be manufactured at a very low cost.

• Disadvantages: Because this is a cutting-edge materials innovation, the primary disadvantage right now is availability. These devices are still not yet in widespread, everyday clinical use.

Common Uses

Currently, traditional diagnostic ultrasound is an "episodic" event—the patient comes to the clinic, is scanned by a sonographer for 20-60 minutes, and leaves. 

These new flexible transducers can expand Point-of-Care Ultrasound (POCUS) into the realm of continuous, wearable patient monitoring. Because they are inexpensive and stick to the skin like a bandage, they can be worn by the patient over long periods to continuously monitor internal organs or vascular hemodynamics.

The Future of the Technology

As these flexible, low-cost patches move beyond the prototype phase, they may fundamentally change how and where we scan. We can expect to see this technology combined with wireless transmission and Artificial Intelligence. This will allow ultrasound to expand beyond the hospital walls and directly into home healthcare. Imagine a patient wearing an ultrasound patch under their clothes that continuously monitors their cardiac function, automatically sending the data to a sonographer or physician miles away!

Reference: in Guo, Jing Liu, Ying Li, Ruixia Xu, Guangsheng Song, Jianan Wu, Zhihui Qian, Lei Ren, Luquan Ren, Qiang Zhou, Wearable flexible ultrasonic transducers: materials, applications, and challenges, Ultrasonics, Volume 159, 2026, 107872, ISSN 0041-624X, https://doi.org/10.1016/j.ultras.2025.107872. (https://www.sciencedirect.com/science/article/pii/S0041624X25003099)