Effects of Microwave‐Assisted Cross‐Linking on the Creep Resistance and Sensing Accuracy of a Coaxial‐Structured Fiber Strain Sensor

Abstract Nanocomposites have been widely studied for sensor applications because of their high design flexibility. However, the creep behavior of polymeric materials is a crucial issue of nanocomposite‐based strain sensors in terms of sensing accuracy in high‐temperature environments, which acts as a bottleneck for the use of nanocomposites in embedded type sensors for monitoring the curing reactions and structural health of composite. Herein, we suggest a microwave‐assisted cross‐linking method for enhancing the reliability of polymer‐based coaxial‐structured fiber strain sensors in high temperatures. A dry‐jet wet‐spun ultra‐high molecular weight polyethylene core fiber with a microwave post‐treatment in a peroxide bath provided superior strength (2.1 GPa), modulus (69 GPa), and enhanced creep resistance (>94%). By using a creep resistance‐enhanced core fiber, coaxial‐structured fiber strain sensors, which have multi‐layer structured shell parts, could be fabricated via the simple dip‐coating method. The fabricated coaxial‐structured fiber strain sensor showed a high gauge factor (4.12 with strain range of 0%–1%), a low‐temperature sensitivity coefficient (−6.5 × 10 −4 ), and an improved sensing accuracy (<3% error at 80 °C) in high‐temperature environments. From these results, it can be confirmed that the microwave‐assisted cross‐linking method is very promising for use in nanocomposite‐based strain sensors for various application fields.