Nacre-inspired MXene-based film for highly sensitive piezoresistive sensing over a broad sensing range

As the main component of wearable electronic equipment, flexible pressure sensors have attracted wide attention due to their excellent sensitivity and their promise with respect to applications in health monitoring, electronic skin, and human–computer interactions. However, it remains a significant challenge to achieve epidermal sensing over a wide sensing range, with short response/recovery time and featuring seamless conformability to the skin simultaneously. This is critical since the capture of minute electrophysiological signals is important for health care applications. In this paper, we report the preparation of a nacre-like MXene/sodium carboxymethyl cellulose (CMC) nanocomposite film with a “brick-and-mortar” interior structure using a vacuum-induced self-assembly strategy. The synergistic behavior of the MXene “brick” and flexible CMC “mortar” contributes to attenuating interlamellar self-stacking and creates numerous variable conductive pathways on the sensing film. This resulted in a high sensitivity over a broad pressure range (i.e., 0.03–22.37 kPa: 162.13 kPa⁻¹; 22.37–135.71 kPa: 127.88 kPa⁻¹; 135.71–286.49 kPa: 100.58 kPa⁻¹). This sensor also has a low detection limit (0.85 Pa), short response/recovery time (8.58 ms/34.34 ms), and good stability (2000 cycles). Furthermore, we deployed pressure sensors to distinguish among tiny particles, various physiological signals of the human body, space arrays, robot motion monitoring, and other related applications to demonstrate their feasibility for a variety of health and motion monitoring use cases.

Graphic abstract