Flexible Strain Sensors Based on Printing Technology: Conductive Inks, Substrates, Printability, and Applications

Printing technology has revolutionized manufacturing by enabling high-volume, multipurpose, low-cost production with minimal environmental impact. This advancement has led to the integration of flexible electronic devices, such as displays, actuators, and sensors, into various consumer markets. Over the past few decades, printed electronics have garnered significant interest from both academic and industrial communities. Among these, flexible strain sensors stand out due to their adaptability and potential for large-scale applications. However, a comprehensive analysis of their sensing performance, particularly with respect to printability, remains lacking. This review aims to systematically explore the development of flexible strain sensors produced through printing technology, focusing on key aspects such as the formulation of conductive inks, the use of diverse substrate materials, and the challenges associated with printability. Additionally, it delves into the practical applications of these sensors across multiple industries. By providing an in-depth examination of these factors, this review offers valuable insights into the current state of printed electronics and highlights their future potential in advancing flexible sensing technologies.