Enabling a Paper-Based Flexible Sensor to Work under Water with Exceptional Long-Term Durability through Biomimetic Reassembling of Nanomaterials from Natural Wood

Abstract

Paper-based sensors have many distinguishing advantages; however, how to improve their working durability especially under water is a critical issue in many applications and unfortunately remains a huge challenge. In this work, we design and develop an innovative strategy enabling paper-based strain and pressure sensors to work under water with exceptional long-term working durability by biomimetic reassembling of nanomaterials from natural wood. A composite paper consisting of softwood fibers and 22 wt % graphite nanoplates was prepared based on a papermaking protocol. Cellulose nanofibers were added to strengthen the composite paper, and lignin nanoparticles were applied onto the paper surface via the paper coating technology to obtain its superhydrophobicity. Subsequently, the as-obtained superhydrophobic composite paper was assembled into a flexible sensor that can be used to detect strain and pressure changes both in air and under water. As the strain sensor, its gauge factor was 10.9 and 14.6 in air and under water, and the corresponding response time was 0.3 and 0.15 s, respectively. Surprisingly, an exceptional working stability was achieved even after more than 10,000 bending–unbending cycles under water. As the pressure sensor, its sensitivity (S) was 0.02 and 0.38 kPa–1 in air and under water, and the corresponding response time was 0.46 and 0.3 s, respectively. Its long-term durability can also exceed 10,000 pressing–releasing cycles. This novel strategy developed in this work can be an effective approach for biomimetic re-engineering of biomass-derived nanomaterials, aiming to develop highly stable paper-based flexible sensors that can find applications in wearable systems and underwater equipment.

A flexible paper based strain sensors drawn by pencil for low-cost pressure sensing applications

“…The flexibility of silicon substrates, achieved through processes like chemical-mechanical polishing reducing the substrate thickness to submicron levels, enhances the adaptability of such sensors [15]. Notably, paper, characterized by its softness, cost-effectiveness, and lightweight properties, has garnered considerable attention as an environmentally friendly substrate [16]− [18]. Previous research has explored paper-based sensors for various applications, including strain measurement, there remains a significant research gap in terms of leveraging common materials like paper and graphite to develop low-cost, environmentally sustainable sensors with enhanced performance characteristics.…”

Bio-Inspired Nanomaterials for Micro/Nanodevices: A New Era in Biomedical Applications

“…Bio-inspired nanomaterials (BINMs), alternatively referred to as biomimetic nanomaterials (BNMs), are a class of materials that are intentionally engineered and manufactured to replicate the intricate structures, functionalities, or mechanisms observed in natural biological systems [ 1 , 2 , 3 ]. These advancements offer a novel trajectory for the field of material science, facilitating the creation of materials possessing unique characteristics that can effectively tackle a wide range of scientific, technological, and environmental obstacles through successful applications in multidimensional sectors, including medicine and healthcare [ 4 ], biotechnology and bioengineering [ 5 ], energy [ 6 ], environment [ 7 ], material science [ 8 ], robotics [ 9 , 10 ], and many more [ 11 , 12 , 13 ]. Various biological entities, including proteins, DNA [ 14 , 15 ], cells [ 16 ], and complete organisms [ 17 ], can serve as sources of inspiration for these materials.…”

A Review of Paper-Based Sensors for Gas, Ion, and Biological Detection

“…By evaluating the sensors' resistance to bending and other mechanical stresses, their durability can be quantified. Thus, the mechanical properties of the sensors play a significant role in their overall performance and long-term reliability [76,77].…”