Inorganic-skeleton-based biofouling-resistant flexible sensor based on HAPNW/ASF/CNT composite for sustainable wearable motion monitoring

A inorganic, biocompatible material system that replaces non-degradable petroleum-based polymers was proposed. • The sensor achieves a rapid response time and equally fast recovery time, excellent cyclability (>4000 cycles). • The sensor exhibits superhydrophobicity, self-cleaning capability, and anti-biofouling properties. • The sensor demonstrates remarkable resistance to mechanical abrasion, UV irradiation, and microbial adhesion. Conventional flexible sensors often suffer from inherent trade-offs among performance, durability, and environmental sustainability. To address these challenges, we propose a novel, inorganic-skeleton-based ternary composite film composed of hydroxyapatite nanowires (HAPNWs), aluminum silicate fibers (ASFs), and carbon nanotubes (CNTs) for high-performance and eco-friendly wearable motion sensing. The film is fabricated via a facile and green wet-process, and its microstructure and conductivity are optimized by tuning the CNT content (defined as the weight ratio of CNTs to the total weight of HAPNWs and ASFs). At an optimal loading of 15 wt%, a uniform and continuous 3D conductive network is formed, enabling the sensor to exhibit a high real-time sensitivity with a rapid response time of 388 ms and an equally fast recovery time of 290 ms, as well as excellent stability over thousands of bending cycles. Furthermore, a synergistic hydrophobic modification using stearic acid and polydimethylsiloxane (PDMS) endows the film with superhydrophobicity (water contact angle >150°), self-cleaning capability, and outstanding anti-biofouling properties. The robust inorganic HAPNW/ASF skeleton ensures remarkable thermal stability (up to 250°C) and chemical inertness, while the hydrophobic coating provides exceptional resistance to mechanical abrasion, UV irradiation, and liquid penetration. This work demonstrates a sustainable material strategy that replaces petroleum-based polymers with a biocompatible inorganic matrix as the structural backbone, offering a promising platform for durable, high-performance wearable sensors and electronic skins in demanding environments. Download: Download high-res image (224KB) Download: Download full-size image