Hyperelastic Graphene Aerogels Reinforced by In-suit Welding Polyimide Nano Fiber with Leaf Skeleton Structure and Adjustable Thermal Conductivity for Morphology and Temperature Sensing

Abstract

Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors. However, graphene sheets are prone to slips under repeated compression due to inadequate chemical connections. In addition, the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research, making it difficult to perform real-temperature detections. To address these issues, a hyperelastic polyimide fiber/graphene aerogel (PINF/GA) with a three-dimensional interconnected structure was fabricated by simple one-pot compounding and in-situ welding methods. The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers, which can effectively avoid slidings between fibers to form reinforced ribs, preventing graphene from damage during compression. In particular, the inner core of the fiber maintains its macromolecular chain structure and toughness during welding. Thus, PINF/GA has good structural stabilities under a large strain compression (99%). Moreover, the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains, with its thermal-conductivity change ratio reaching up to 9.8. Hyperelastic PINF/GA, with dynamically stable thermal and electrical conductivity, as well as high heat tolerance, shows broad application prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments.

Graphical Abstract

Polyimide fibers in graphene aerogel are in-suit welded to fabricate a composite with excellent hyperelasticity and adjustable thermal conductivity for artificial intelligence sensing over a wide temperature range.

Funding

National Natural Science Foundation of China(51973152); Science Fund for Distinguished Young Scholars of Tianjin(19JCJQJC61700)