Here, a highly flexible and anisotropic strain sensor based on sustainable biomass‐derived materials is fabricated through a facile, low‐cost, and scalable approach. The commercially available crepe paper made of the abundant and renewable cellulose is converted into a conductive network by carbonization. The fabricated strain sensor based on this carbonized crepe paper (CCP) exhibits high flexibility, fast response time (<115 ms), high durability (>10 000 cycles), and negligible hysteresis. Especially, the CCP strain sensor shows dramatically different gauge factors (10.10 and 0.14, respectively) between tensile bending perpendicular and parallel to the fibers direction. This anisotropic sensing performance is inherited from the crepe paper's unique anisotropic structure, i.e., aligned cellulose fibers and a corrugated surface, which is well maintained in the CCP. In addition, the CCP strain sensors' practical use in detecting complex human motions and controlling a 2‐degree‐of‐freedom machine is demonstrated, indicating their potential applications in multidimensional wearable electronics and smart robots.

Recently, cellulose paper based materials have emerged for applications in wearable "green" electronics due to their earth abundance, low cost, light weight, flexibility, and sustainability. Herein, for the first time, we develop an almost all cellulose paper based pressure sensor through a facile, cost-effective, scalable, and environment-friendly approach. The screen-printed interdigital electrodes on the flat printing paper and the carbonized crepe paper (CCP) with good conductivity are integrated into a flexible pressure sensor as substrates and active materials, respectively. The porous and corrugated structure of the CCP endows the pressure sensor with high sensitivity (2.56-5.67 kPa in the range of 0-2.53 kPa), wide workable pressure range (0-20 kPa), fast response time (<30 ms), low detection limit (∼0.9 Pa), and good durability (>3000 cycles). Additionally, we demonstrate the practical applications of the CCP pressure sensor in detection of finger touching, wrist pulse, respiration, phonation, acoustic vibration, etc., and real-time monitoring of spatial pressure distribution. The proposed CCP pressure sensor has great potentials in various applications as wearable electronics. Moreover, the subtle fabrication of the desired materials based on commercially available products provides new insights into the development of green electronics.

Wood-derived sustainable materials like cellulose fibers have received increased attention for replacing nonrenewable substrates in emerging high-tech applications. Herein, for the first time, we fabricated a superhydrophobic (static contact angle = 159.6°, sliding angle = 5.8°), highly transparent (90.2%) and hazy (46.5%) nanopaper made of TEMPO-oxidized cellulose nanofibrils (TOCNF) and polysiloxanes. The original TOCNF nanopaper endowed excellent optical and mechanical properties; the constructed pearl-necklace-like polysiloxanes fibers on the nanopaper surface by further silanization significantly improved water-repellency (70.7% for static contact angle) and toughness (118.7%) of the TOCNF nanopaper. Our proposed novel nanopaper that simultaneously achieved light-management and self-cleaning capabilities not only led to an enhancement (10.43%) in the overall energy conversion efficiency of the solar cell by simply coating but also recovered most of the photovoltaic performance losses due to dust accumulation by a self-cleaning process, indicating its potential application in solar cells. This study on cellulose-based multifunctional substrates provided new insights into the future development of sustainable functional devices.

Light-management (LM) films that can regulate transmitted light are significant to diverse fields, such as optoelectronics and energy-efficient buildings. However, for conventional LM films made from petroleum-based polymers, the nonbiodegradability and complicated fabrication process remain a challenge. Herein, we prepare sustainable lignocellulose-based films with excellent light-management capability by facile dissolution and regeneration of wood pulp and the corncob residue from xylitol production (CRXP). The obtained films exhibit high transparency (78%), high haze (61%), and especially remarkable UV-blocking performance (99.94% for UVB and 98.04% for UVA). They achieve consistent indoor light distribution and UV radiation shielding by light management for the application of smart buildings. Furthermore, by spray-coating with SiO2 nanoparticles to construct hierarchical networks, the films are endowed with a superhydrophobic surface with a self-cleaning function to mitigate dust accumulation. Our work provides novel insights into the conversion of lignocellulosic waste to desirable and sustainable functional materials.

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