Reviewed by Lexie CornerSep 6 2024
A study published in the International Journal of Extreme Manufacturing by Prof. Kaichen Xu and his colleagues at Zhejiang University outlines a hybrid laser direct writing technique that enables the creation of functional copper interconnects and carbon-based sensors within a single, integrated system.
(a) Schematic of the LISS on the surface of engineering thermoplastics applied in aircrafts. The LISS is composed of sensors, conductive interconnects and signal processing modules. (b) Schematic of LIP-Cu interconnects for LISS fabricated by a continuous wave green laser. (c) Schematic of LIC sensors for LISS fabricated by an infrared laser. Some figure elements were created using BioRender.com. Image Credit: Kaichen Xu, Zimo Cai, Huayu Luo, Xingyu Lin, Geng Yang, Haibo Xie, Seung Hwan Ko and Huayong Yang.
Using laser technology, the researchers developed a groundbreaking method for directly integrating sensor systems into engineering thermoplastics. This innovation has the potential to enhance safety and extend the service life of critical equipment across various industries, including aerospace, automotive, healthcare, and transportation.
The technology allows for real-time temperature monitoring over extended periods, ensuring optimal performance and reliability.
The XU research group at Zhejiang University (ZJU) is a highly multidisciplinary team focused on advancing the manufacturing of flexible and conformal electronics for wearable and implantable monitoring, whether in everyday or extreme conditions.
Our research mainly includes the development of innovative fabrication techniques, multifunctional devices, as well as system level applications. Based on the principle of laser and matter interactions, we focus on manufacturing of versatile devices mainly using hybrid (ultrafast) laser processing platforms, which are endowed with multitasking features.
Kaichen Xu, Study Corresponding Author and Professor, Zhejiang University
The integration of sensors with engineering thermoplastics allows the materials to monitor their own health and the surrounding environment. Copper (Cu), a highly conductive and cost-effective element in sensor systems, presents challenges due to its tendency to oxidize during and after processing.
Prof. Xu's lab addressed this issue by developing a one-step photothermal treatment that produces durable Cu interconnects capable of resisting oxidation at temperatures as high as 170 °C. The process involves two critical steps: photothermal reduction and passivation of CuO using a continuous wave (CW) laser to create functional copper interconnects, and the use of an infrared (IR) laser to form laser-induced carbon (LIC) sensors from the thermoplastic substrate.
This technique enabled simultaneous reduction, sintering, and passivation of the copper, significantly improving its oxidation resistance at elevated temperatures. The integrated sensor system was then tested for durability and performance in real-time temperature monitoring across various environmental conditions.
This method holds great promise for applications in industries such as aerospace, automotive, high-speed rail, and medical devices. It provides a lightweight, long-lasting solution for real-time monitoring of temperature and other environmental factors.
As the team continues refining this technology, they are exploring ways to expand the system’s capabilities by incorporating additional sensor units for monitoring pressure, strain, and humidity. Their ultimate goal is to develop advanced manufacturing processes that enable the production of high-quality, conformal electronics on curved surfaces, overcoming the limitations of flat surfaces.
Journal References:
Xu, K., et. al. (2024) An in-situ hybrid laser-induced integrated sensor system with antioxidative copper. International Journal of Extreme Manufacturing. doi.org/10.1088/2631-7990/ad6aae