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Preparation of all-cellulose composites with optical transparency using the banana pseudostem as a raw material
摘要： Biopolymers are intended to substitute the petroleum-based polymers and all-cellulose composite has emerged as a green alternative, especially if it can be prepared through a method consuming less energy and fewer chemicals. Here, a novel approach to obtain a nanocomposite film made of cellulose fibrils imbibed into a nanocellulose matrix is described. Banana pseudostem was used as raw material and characterized along with the resulting materials using scanning electron microscopy, optical microscopy and Raman spectroscopy, while the cellulose/nanocellulose film was studied through X-ray diffraction, UV–Vis-NIR spectroscopy and laser scanning microscopy. Results indicate that cellulose (fibrils) and nanocellulose (platelets), extracted from banana pseudostem were successfully purified using hydrolysis at a relatively low amount of chemicals. Transparent films made of a fibrils/nanoplatelets blend were prepared by the solution casting method, exhibiting a transmittance of & 83–88% and a crystallinity index of & 70, hence demonstrating the feasibility of this novel method to obtain cellulose/nanocellulose free-standing films.
关键词： Nanocomposites,Cellulose nanoplatelets,Cellulose/nanocellulose films,Agricultural waste,Inner pseudostem
更新于2025-11-21 11:08:12
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Flexible TiO2-coated nanocellulose membranes incorporated with CdTe as electrodes in photoelectrochemical cells
摘要： Incorporation of quantum dots (QDs) into porous matrices has triggered the development of novel optical devices. In this work, TiO2 sensitized by CdTe incorporated into bacterial nanocellulose (BNC) membranes were tested as photoelectrodes in a photoelectrochemical cell directed to the water splitting for hydrogen generation. The flexible membranes were produced by immersing BNC membranes in an aqueous solution of CdTe capped with glutathione (CdTe–GSH) and further deposited over a thin layer of TiO2. Incorporation of CdTe–GSH into BNC membranes was confirmed by infrared spectroscopy. Fluorescence spectroscopy revealed that the luminescence intensity increased with the immersion time in the CdTe–GSH solution. Field-emission gun scanning electron microscopy (FEG-SEM) images revealed that the CdTe/QDs (5 nm) were homogeneously dispersed on the cellulose nanofibers. BNC/CdTe–GSH membranes was tested as photoelectrodes. Photoelectrochemical cells exhibited a significant photocurrent in wavelengths ranging from 400 to 800 nm, which indicates their potential for applications as flexible electrodes, sensors and photovoltaic systems.
关键词： Photoelectrochemical cell,Quantum dots,Bacterial nanocellulose,Water splitting,Hydrogen generation
更新于2025-09-23 15:21:21
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Plasmonic colored nanopaper: a potential preventive healthcare tool against threats emerging from uncontrolled UV exposure
摘要： Preventive healthcare is crucial to hinder or delay the onset of disease, furthermore it contributes to healthy and productive lifestyles and saves resources allocated to public health. Herein, we explore how the plasmonic coupling of silver and gold nanoparticles embedded within nanopaper allows for potential preventive healthcare tools based on a change in plasmonic color. Particularly, we selected UV radiation exposure as a potential threat to health to be monitored via plasmonic colored nanopaper (PCN). Uncontrolled UV radiation exposure is not only known to provoke epidermal damage, but also to trigger leaching of hazardous compounds from polycarbonate containers. In this context, we engineered UV-responsive PCN devices whose sensing mechanism is based on UV photodegradation of silver nanoparticles. Since absorbance and scattering of metal nanoparticles strongly depend on their size and inter-particle distance, the resulting PCN detectors are able to warn of the potential UV radiation-induced threat via a visually observable plasmonic color change with a yellowish/reddish transition. Epidermal experiments with tattoo-like PCN devices prove the resulting detectors can change in color upon safe dose of sun exposure. Moreover, PCN detectors stuck on polycarbonate containers also change in color after moderate sun exposure. This cost-effective and lightweight nanophotonic device leads to a versatile preventive healthcare tool.
关键词： smart packaging,nanoplasmonics,wearable devices,nanocellulose,nanophotonics
更新于2025-09-23 15:19:57
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Thermally Superstable Cellulosic-Nanorod-Reinforced Transparent Substrates Featuring Microscale Surface Patterns
摘要： The recent rapid expansion of thin-film, bendable, and wearable consumer (opto)electronics demands flexible and transparent substrates other than glass. Plastics are the traditional choice, but they require amelioration because of their thermal instability. Here, we report the successful conversion of a soft and thermally vulnerable polymer into a highly thermally stable transparent nanocomposite material. This is achieved by the meticulous choice of a polymer with a glass-transition temperature below 0 °C that gives stable mechanics above room temperature, reinforcing the polymer with a load-bearing hierarchical network of the incredibly strong and stable natural material: cellulose nanorods. Owing to the Pickering emulsification process, the nanocomposites inherit the self-assembled structural hierarchy from the cellulose nanorod-encapsulated resin droplets. The ameliorated nanocomposites have highly desirable high-temperature endurance (～150?180 °C) in terms of the thermomechanical, thermodimensional, and thermo-optical performance. Any photonic nano- or microstructures can be directly molded on the surface of the nanocomposites in high precision for better light management in photonic and optoelectronic applications. The highlight of this work is the demonstration of a highly thermally stable microlens array on the ameliorated transparent nanocomposite.
关键词： thermal stability,polymer nanocomposites,flexible electronics,Pickering emulsion,microlens array,nanocellulose
更新于2025-09-19 17:15:36