Cellulose Nanomaterials Research Articles

Greener Production and Application of Slow-Release Nitrogen Fertilizer Using Plasma and Nanotechnology: A Review

The potential of both plasma and nanotechnology in producing slow-release fertilizer is immense. These technologies, when combined, may offer green and inexpensive nitrogen fertilizers, from rich renewable resources available in local areas. Together, these technologies may overcome some limitations of conventional synthetic fertilizers, which are currently expensive and associated with low nitrogen use efficiency and significant environmental concerns. This review explores the utilization of recent advances in plasma and nanotechnology, which can be leveraged to create new slow-release nitrogen fertilizers. It emphasizes their crucial role in addressing nitrogen depletion and improving crop production. Despite the lack of attempts to develop slow-release nanofertilizers from low-cost liquid nitrate generated by emission-free nonthermal plasma, the effectiveness of plasma nitrate matches that of conventional fertilizer for crop production. We propose a more efficient electrocatalytic conversion of plasma nitrate to ammonium salt, then coating it with plant-based cellulose nanoparticles to create a slow-release form. This set of processes would synchronize nutrient release with the dynamic N requirements of plants. Formulations using agro-based, low-cost cellulose nanomaterials could replace high-cost carrier hydrogels associated with low mechanical strength. This review also highlights the isolation of nanocellulose from various plant materials and its characterization in different formulations of slow-release nanoplasma N fertilizer. Additionally, we discuss mechanisms of N loss, slow-release, and retention in the soil that can contribute to the production and use of efficient, sustainable fertilizers to improve food security and, consequently, the health of our planet.

Cellulose-Templated Nanomaterials for Nanogenerators and Self-Powered Sensors.

Energy crisis inspires the development of renewable and clean energy sources, along with related applications such as nanogenerators and self-powered devices. Balancing high performance and environmental sustainability in advanced material innovation is a challenging task. Addressing the global challenges of sustainable development and carbon neutrality lead to increasedinterest in biopolymer research. Nanocellulose materials, derived from biopolymers, demonstrate potential as template candidates for advanced materials, due to their unique properties, including high strength, high surface area, controllable pore structures and high-water retention. In recent years, cellulose-templated nanomaterials enable delicate nano-/microscale structural construction, thus promoting developments in the field of nanogenerators and self-powered sensors. However, there is still a limited number of reviews focused on cellulose-templated nanomaterials for applications in nanogenerators and self-powered sensors. This review aims to fill this research gap by introducing various cellulose-templated nanomaterials and providing a detailed analysis of their fashionable applications in nanogenerators and self-powered sensors. The goal is to present cellulose-templated nanomaterials as highly promising template and guest materials for templating technologies, offering sustainable nano-/microscale control over advanced materials for the foreseeable future. This potential is promising for new applications in the fields of nanogenerators and self-powered sensors.

A review of electrical and piezoelectric properties of nanocellulose biocomposites

Abstract The increasing request for lightweight, environmentally sustainable materials with versatile functionality and strong mechanical properties is driving renewed interest in nanocellulose for electrical applications. Nanocellulose, a biologically derived polymeric nanomaterial, has seen significant growth in the global market due to advancements in nanotechnology and the increasing need for sustainable materials. This has accelerated research into the development of cellulose-based nanomaterials. However, nanocellulose on its own does not inherently possess the ability to function as a conductive material. To address this limitation, researchers have explored various modifications, such as combining nanocellulose with conductive materials or applying specific chemical treatments. These approaches have been shown to enhance the electrical conductivity of nanocellulose, making it suitable for use in electrically conductive composites. Over the past few decades, nanocellulose composites have been extensively studied for their applications in energy, electronics, biomedicine, health, and environmental sectors. Nanocellulose possesses a unique combination of exceptional properties, including biodegradability, renewability, and a distinctive fibrous structure, proving that it is the best choice for these uses. The superior electrical properties of nanocellulose-based composites, coupled with their flexibility, ease of production, and biocompatibility, make them highly desirable for various advanced technological applications. Significant advancements have been achieved by researchers in fabricating various types of nanocellulose materials and exploring their potential in nanogenerators, humidity sensors, gas sensors, and supercapacitors. The ability to modify the surface of nanocellulose and its robust properties offer numerous opportunities for creating hybrid materials within the electrical domain.

Cellulose nanomaterial metrology: microscopy measurements.

Cellulose nanomaterials are increasingly used for a wide variety of applications. Adequate characterization of these materials is required for quality control during production, to distinguish between materials synthesized by different methods, by different suppliers or from difference cellulose biomass sources, to facilitate development of applications and for regulatory purposes. Here we review recent microscopy measurements for the three main types of cellulose nanomaterials: cellulose nanocrystals, individual cellulose nanofibrils and cellulose nanofibrils. Atomic force microscopy and both scanning and transmission electron microscopy are covered with a focus on recent studies that have metrological rigor, rather than qualitative investigations. In some cases results are compared to those obtained by other methods that are more likely to see widespread use for routine quality control measurements. Detailed studies that use microscopy to provide insight on fundamental material properties (e.g., chiral properties) are also included. Particle size and morphology are important properties but are challenging to measure for cellulose nanomaterials due to the rod or fibril shaped particles, their propensity to agglomerate and aggregate, their low contrast for electron microscopy and, for cellulose nanofibrils, the complex branched and interconnected structures. Overall, the results show that there are now a number of studies in which attention to metrological detail has resulted in measurements that allow one to compare and distinguish between different materials, although there are still examples for which it is not possible to draw conclusions on size differences. The use of detailed microscopy protocols that yield accurate and reliable results will be beneficial in material production and addressing regulatory requirements and will allow the validation of other methods that are more amenable to routine measurements.

Effect of catalyst and oxidant concentrations in a TEMPO oxidation system on the production of cellulose nanofibers.

In traditional TEMPO oxidation systems, the high cost of TEMPO catalysts has been a significant barrier to the industrialization of oxidized CNF. From an economic perspective, presenting the characteristics of various CNFs produced with the oxidation systems with reduced catalyst usage could facilitate the industrial application of CNF across a wide range of fields. In this study, it was demonstrated that reducing the amount of TEMPO catalyst used (from 0.1 to 0.05 mmol g-1) in a conventional oxidation system increased the carboxylate content by approximately 6.3%. Furthermore, the activation of hydroxyl amine TEMPO, which is generated after the oxidation reaction of cellulose, was enhanced by adjusting the dosage of the inexpensive oxidant NaClO, leading to a 20% improvement in carboxylate content. This suggests that controlling the amount of NaClO as an oxidant can be a key parameter in adjusting the dosage of TEMPO to achieve the targeted degree of surface substitution. Results from the dispersion stability, UV-transmittance, and morphological properties of TEMPO-oxidized CNF using microfluidizing treatment showed that high carboxylate content plays a crucial role in producing high-purity CNF suspensions, which are small, uniform, and free from microfibers. Additionally, by varying the number of mechanical treatments applied to the oxidized cellulose, various types of CNF suspensions with different mean widths were obtained. We expect that these findings offer meaningful insights to end-users seeking a breakthrough in the performance limitations of final applications using cellulose nanomaterials.

Methods for Fabrication of Self/Free Standing Nanocellulose (NC)-Nano Montmorillonite (N-MMT) Composite Films/Sheets — A Review

Plastic pollution looms large as a formidable foe to the environment. Enter cellulose nanofibers, the shining stars in the quest for innovative, eco-friendly paper-based packaging that is not just renewable, but also recyclable and biodegradable. These cellulose wonders boast impressively low oxygen permeability, but when it comes to water vapor, they fall short compared to traditional packaging plastics like LDPE. To tackle this challenge, researchers have been crafting composites by blending cellulose nanofibers with inorganic nanoparticles, such as Montmorillonite clay, which helps to curb water vapor permeability. However, this clever addition comes with a catch — it further complicates the already tricky drainage process during layer formation via vacuum filtration. This review delves into the complex world of nano cellulose-nano-MMT (Montmorillonite) composites, examining their preparation processes, unique characteristics, wide-ranging uses, and their significant contribution to promoting circular economy principles. By combining cellulose nanomaterials with MMT, a synergistic approach is taken to develop a new composite material with improved mechanical, thermal, and barrier properties. Various fabrication techniques are explored, including solution blending, in-situ polymerization, and electrospinning, allowing for customized design and optimization of the composite material. The review discusses how the nano cellulose-MMT composite demonstrates enhanced mechanical strength, thermal stability, and barrier properties, positioning it as a sustainable option compared to traditional materials. The review also showcases the diverse applications of these nano-composites in fields like packaging, biomedical devices, and environmental cleanup, emphasizing their alignment with circular economy principles. By examining the entire life cycle of these composites, from production to use and eventual disposal or recycling, the review underscores their role in supporting a circular economy. In light of the ongoing efforts by the scientific community and various industries to identify environmentally sustainable solutions, it is imperative to comprehend the synthesis, properties, and applications of nano cellulose-MMT composites. This understanding is essential for advancing sustainable processing for green material development.

Hybrid nanocellulose material as an adsorbent to remove reactive yellow 2 dye

Textile dyes are frequently disposable in aqueous effluents, making it difficult to remove them from industrial effluents before their release to natural waters. This paper deals with the fabrication of cellulose-based adsorbents by reacting nanocelulose crystalline (nanocel) with N-[3-(trimethoxysilyl)propyl]ethylenediamine (TMSPEDA), forming the hybrid (silylpropyl)ethylenediamine@nanocellulose (SPEDA@nanocel), which was employed as adsorbent for the uptake of reactive yellow 2 dye (RY-2) from aqueous effluents. Characterisation of SPEDA@nanocel was carried out using FTIR, SEM–EDS, XRD, TGA, surface area, pHpzc, and hydrophobicity/hydrophilicity ratio (HI). Also, adsorption studies were thoroughly investigated. The effect of initial pH indicated that the maximum uptake of RY-2 takes place at pH 2, which is an indication of the electrostatic mechanism. The kinetic data carried out with 250 and 500 mg L−1 RY-2 with SPEDA@nanocel followed better the nonlinear fractional-like pseudo-first-order model. The t0.5 and t0.95 for the dye uptake were about 30 and 141 min, respectively. The equilibrium data from 10 to 45 °C indicated that the Liu isotherm model was the best-fitted isothermal model. The maximum sorption capacity attained was 112.3 mg g−1 at 45 °C. The thermodynamic data have shown that the equilibrium was favorable and endothermic, and the ΔH° was compatible with an electrostatic attraction between RY-2 and SPEDA@nanocel. Experiments of desorption of loaded adsorbent showed promising results for real applications since at least 5 adsorption/desorption cycles could be employed without significant changes in the recovery and with high precision.

Cardamom Pickering emulsions stabilized by cellulose nanostructures as disinfection agents against bacteria and SARS-CoV-2

This study introduces a new disinfectant agent utilizing cardamom essential oil stabilized by cellulose nanomaterials (CN). The Pickering emulsion technique prevented oil degradation and extended its storage duration. Cellulose nanocrystals (CNC) or cellulose nanofibers (CNF) were utilized as stabilizers, and the emulsions were evaluated for surface tension, rheology, morphology, antimicrobial and antiviral activity against S. enterica, S. aureus, P. aeruginosa, E. coli, and SARS-CoV-2. Surface tension measurements indicated an electrostatic stabilization mechanism in CNC emulsions, exhibiting fluid behavior confirmed by rheological tests. On the other hand, CNF emulsions displayed drop packaging, characteristic of shear-thinning behavior, as confirmed by the Ostwald-de-Waele model. The emulsions exhibited antibacterial activity against S. aureus and P. aeruginosa, particularly the CNC samples, suggesting that nanocellulose alters the regulation of oil migration into the medium. Testing against SARS-CoV-2 revealed that cardamom essential oil required 30 min of contact for viral protein denaturation, while CNC and CNF emulsions took 60 and 50 min, respectively. This indicates that CN acts as an encapsulating agent, prolonging the oil’s release time and necessitating longer contact periods with the virus. These findings demonstrate the potential of these emulsions in developing new antimicrobial and antiviral products.

An enzymatic hydrolysis-based platform technology for the efficient high-yield production of cellulose nanospheres

This study evaluates the feasibility of using enzymatic technology to produce novel nanostructures of cellulose nanomaterials, specifically cellulose nanospheres (CNS), through enzymatic hydrolysis with endoglucanase and xylanase of pre-treated cellulose fibers. A statistical experimental design facilitated a comprehensive understanding of the process parameters, which enabled high yields of up to 82.7 %, while maintaining a uniform diameter of 54 nm and slightly improved crystallinity and thermal stability. Atomic force microscopy analyses revealed a distinct CNS formation mechanism, where initial fragmentation of rod-like nanoparticles and subsequent self-assembly of shorter rod-shaped nanoparticles led to CNS formation. Additionally, adjustments in process parameters allowed precise control over the CNS diameter, ranging from 20 to 100 nm, highlighting the potential for customization in high-performance applications. Furthermore, this study demonstrates how the process framework, originally developed for cellulose nanocrystals (CNC) production, was successfully adapted and optimized for CNS production, ensuring scalability and efficiency. In conclusion, this study emphasizes the versatility and efficiency of the enzyme-based platform for producing high-quality CNS, providing valuable insights into energy consumption for large-scale economic and environmental assessments.

Surface modification of cellulose nanomaterials with amine functionalized fluorinated ionic liquids for hydrophobicity and high thermal stability

A highly hydrophobic fluorinated ionic liquid (IL), 3-aminopropyl-tributylphosphonium bis(trifluoromethylsolfonyl)imide ([aP4443][NTf2]), was synthesized, and applied for the surface modification of cellulose nanomaterials (CNMs) by reductive amination. The modified CNMs were fully characterized for their chemical structure, morphology, thermal stability, and surface hydrophobicity. Results obtained from Nuclear Magnetic Resonance spectroscopy (1H, 13C, 19F and 31P), Fourier Transform Infrared spectroscopy, X-ray Photoelectron Spectroscopy, and X-ray diffraction confirmed the successful grafting of [aP4443][NTf2] onto the surface of CNMs up to a degree of surface functionalization of 2.5 %. Transmission Electron Microscopy analysis confirmed the dimensions of the CNMs were retained after modification but with significant aggregation for modified cellulose nanocrystals (CNCs). Thermal Gravimetric Analysis demonstrated significant increases in the degradation temperatures of modified CNCs from ∼252 °C to ∼310 °C. Modified cellulose nanofibers (CNFs) did not show any increase in thermal stability. The modified CNM suspensions showed reduced affinity for water and the formation of aggregates in aqueous media. Furthermore, a water contact angle test demonstrated enhanced hydrophobicity for modified CNMs. This modification approach holds potential for the use of the [aP4443][NTf2] IL for functional materials to achieve novel hydrophobic CNMs suitable for aqueous processing with thermoplastics, for fabrication of thermally stable composite materials, and for polymer gel electrolytes for batteries.

TEMPO/CaBr2/Ca(OCl)2 oxidation of hardwood bleached kraft pulp in water at pH 10 with aqueous Ca(OH)2 solution

The conventional TEMPO/NaBr/NaOCl system for oxidation of cellulose to prepare nanocellulose materials has some shortcomings in terms of controlling side reactions and clogging in washing/filtration process. A new TEMPO/CaBr2/Ca(OCl)2 system was then developed to oxidize a hardwood bleached kraft pulp (HBKP) in water at pH 10 (TEMPO = 2,2,6,6-tetramethylpiperidine-1-oxyl radical). An aqueous Ca(OH)2 solution was used to continuously control the reaction mixture at pH 10. After oxidation, the reaction mixture containing the oxidized products and chemicals was directly filtered on a 40-μm-mesh nylon filter and the water-insoluble oxidized products on the filter were washed with water without any clogging. The carboxy content increased to 1.5 mmol/g and the mass recovery ratio decreased to 87.7% as the amount of Ca(OCl)2 was increased to 10.0 mmol/g-HBKP. The oxidized products contained calcium ions but almost no chloride ions, indicating that they comprised almost pure –(COO)2Ca groups. The ready filtration and washing of the oxidized products was probably owing to the low degree of dissociation of the –(COO)2Ca groups in water. The X-ray powder diffraction (XRD) and solid-state carbon 13 nuclear magnetic resonance (13C-NMR) analyses revealed that the crystallinities and crystal widths of the original cellulose I structure were mostly retained in the oxidized products. However, size-exclusion chromatography and viscosity analyses revealed that substantial depolymerization occurred on the cellulose and oxidized cellulose molecules in the products, as in TEMPO/NaBr/NaOCl-oxidized products.Graphical

Nanocellulose: The Ultimate Green Aqueous Dispersant for Nanomaterials.

Nanocellulose, a nanoscale derivative from renewable biomass sources, possesses remarkable colloidal properties in water, mechanical strength, and biocompatibility. It emerges as a promising bio-based dispersing agent for various nanomaterials in water. This mini-review explores the interaction between cellulose nanomaterials (nanocrystals or nanofibers) and water, elucidating how this may enable their potential as an eco-friendly dispersing agent. We explore the potential of nanocellulose derived from top-down processes, nanocrystals, and nanofibers for dispersing carbon nanomaterials, semiconducting oxide nanoparticles, and other nanomaterials in water. We also highlight its advantages over traditional methods by not only effectively dispersing those nanomaterials but also potentially eliminating the need for further chemical treatments or supporting stabilizers. This not only preserves the exceptional properties of nanomaterials in aqueous dispersion, but may even lead to the emergence of novel hybrid functionalities. Overall, this mini-review underscores the remarkable versatility of nanocellulose as a green dispersing agent for a variety of nanomaterials, inspiring further research to expand its potential to other nanomaterials and applications.

Effects of cellulose nanofibrils on rheological and mechanical properties of 3D printable cement composites

This study explores the effects of cellulose nanofibrils (CNF), a relatively new type of nanocellulose material, on the rheological and printability characteristics of cementitious mixtures, and the mechanical properties of 3D printed specimens. The rheology of the mortar mixtures with varying ratios of CNF is thoroughly assessed first. Two testing protocols, stress growth test and ramp test, are followed for rotational measurements using a shear rheometer with a building cell and vane motor. Stress growth tests are carried out to quantify the static yield stress of the cementitious mixtures. Ramp tests are conducted to determine dynamic yield stress and plastic viscosity of the mixes using the Bingham visco-plastic material model. As oscillatory measurements, amplitude sweep tests are carried out to determine the viscoelastic properties of the mortar mixes, including storage modulus and critical strain that are found to be essential for buildability. Thermogravimetric analysis (TGA) is conducted to assess the effects of CNF on the hydration characteristics of the mixtures. The printability and the buildability of the mortar mixtures incorporating CNF are assessed using a 3D concrete printer equipped with a 10 mm diameter nozzle and screw pump mechanism. Tensile, flexural, and compressive strength tests are conducted to determine the mechanical properties of 3D printed specimens with varying ratios of CNFs. Scanning electron microscopy (SEM) is used to conduct the microstructural analysis on fractured surfaces of the mechanically tested specimens. Results indicate that adding CNF at least 0.3 wt% of cement has a favorable effect on the rheological properties of cement composites.

Agricultural Wastes and Their By-Products for the Energy Market

The conversion of lignocellulosic agricultural waste into biofuels and other economically valuable compounds can reduce dependence on fossil fuels, reduce harmful gas emissions, support the sustainability of natural resources, including water, and minimize the amount of waste in landfills, thus reducing environmental degradation. In this paper, the conversion of agricultural wastes into biomethane, biohydrogen, biodiesel, bioethanol, biobutanol, and bio-oil is reviewed, with special emphasis on primary and secondary agricultural residues as substrates. Some novel approaches are mentioned that offer opportunities to increase the efficiency of waste valorization, e.g., hybrid systems. In addition to physical, chemical, and biological pretreatment of waste, some combined methods to mitigate the negative effects of various recalcitrant compounds on waste processing (alkali-assisted thermal pretreatment, thermal hydrolysis pretreatment, and alkali pretreatment combined with bioaugmentation) are evaluated. In addition, the production of volatile fatty acids, polyhydroxyalkanoates, biochar, hydrochar, cellulosic nanomaterials, and selected platform chemicals from lignocellulosic waste is described. Finally, the potential uses of biofuels and other recovered products are discussed.

Application of nanocellulose in food packaging - A SWOT analysis

Environmental concerns due to the wide use of plastic in food packaging have become one of the most significant challenges in the world. Consequently, the research in developing sustainable materials for food packaging has accelerated. Nanocellulose-based packaging is a biodegradable, renewable, and antimicrobial material with some competitive physicochemical characteristics when compared to plastic packaging. However, there has been insufficient research on a holistic discussion of the potentials and drawbacks of nanocellulose as well as its production, applications and disposal regarding sustainability. This study aims to evaluate the application of nanocellulose in food packaging. It gives an exhaustive overview of the essential aspects from the production to disposal of nanocellulose through a literature review. Then, a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis is used to evaluate the potential and drawbacks of applying nanocellulose in food packaging. It has been observed that the physicochemical properties of nanocellulose materials have the potential to be used in food packaging with fewer negative impacts on the environment. Furthermore, it supports the top tiers of the waste hierarchy and a circular economy. However, some challenges need to be addressed to ensure the safe and effective use of nanocellulose in food packaging, including high expenses, a lack of guidelines, and potential hazards to people and the environment. To eliminate these uncertainties, more studies need to be performed on applying nanocellulose in food packaging.

Biocomposites and bionanocomposites from poly(lactide) and cellulosic materials – a review

Abstract Global environmental concerns have recently accelerated interest in the usage of biodegradable polymers to replace petroleum-based conventional plastics. Lactic acid-based polymers are some of the most promising and widely studied biobased materials, which are suitable for packaging and biomedical applications. This is mainly due to their appealing characteristics such as relatively good mechanical properties, biocompatibility, and multiple end-of-life options such as recyclability and biodegradability in industrial composting conditions. However, the use of lactic acid-based polymers in advanced applications is constrained by their inherent brittleness, poor melt strength, and relatively high cost. These disadvantages can be remedied by reinforcement with cellulose nanomaterials which can enhance their mechanical properties while maintaining their biodegradability. This review provides an overview of recent studies on the development of biodegradable lactic acid-based polymer composites and nanocomposites reinforced with cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs) and microcrystalline cellulose (MCC). The different processing methods and chemical modification techniques utilised on modification and functionalisation of cellulosic nanomaterials for improving the properties of lactic acid-based polymer nanocomposites are also discussed.

Effect of Quorum Sensing Molecules on the Quality of Bacterial Nanocellulose Materials.

Bacterial nanocellulose (BNC) biofilms, produced by various bacterial species, such as Gluconacetobacter xylinus, represent a highly promising multifunctional material characterized by distinctive physiochemical properties. These biofilms have demonstrated remarkable versatility as nano biomaterials, finding extensive applications across medical, defense, electronics, optics, and food industries. In contrast to plant cellulose, BNC biofilms exhibit numerous advantages, including elevated purity and crystallinity, expansive surface area, robustness, and excellent biocompatibility, making them exceptional multifunctional materials. However, their production with consistent morphological properties and their transformation into practical forms present challenges. This difficulty often arises from the heterogeneity in cell density, which is influenced by the presence of N-acyl-homoserine lactones (AHLs) serving as quorum sensing signaling molecules during the biosynthesis of BNC biofilms. In this study, we employed surface characterization methodologies including scanning electron microscopy, energy-dispersive spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and atomic force microscopy to characterize BNC biofilms derived from growth media supplemented with varying concentrations of distinct N-acyl-homoserine lactone signaling molecules. The data obtained through these analytical techniques elucidated that the morphological properties of the BNC biofilms were influenced by the specific AHLs, signaling molecules, introduced into the growth media. These findings lay the groundwork for future exploration of leveraging synthetic biology and biomimetic methods for tailoring BNC with predetermined morphological properties.

TEMPO-Oxidized Nanocellulose Films Modified by Tea Saponin Derived from Camellia oleifera: Physicochemical, Mechanical, and Antibacterial Properties.

Nanocellulose materials have been widely used in biomedicine, food packaging, aerospace, composite material, and other fields. In this work, cellulose obtained from Camellia shells through alkali boiling and subbleaching was micro-dissolved and regenerated using the DMAc (N,N-Dimethylacetamide)/LiCl system, and TOCNs (TEMPO-oxidized cellulose nanofibers) with different degrees of oxidation. The membrane was prepared by filtration of polytetrafluoroethylene (pore size 0.1 μm), and the oxidized nanocellulose film was obtained after drying, Then, the crystallinity, mechanical properties and oxygen barrier properties of the TOCN film were investigated. Furthermore, based on TS (tea saponin) from Camellia oleifera seed cake and TOCNs, TS-TOCN film was prepared by the heterogeneous reaction. The TS-TOCN film not only shows excellent oxygen barrier properties (the oxygen permeability is 2.88 cc·m-2·d-1) but also has good antibacterial effects on both Gram-negative and Gram-positive bacteria. The antibacterial property is comparable to ZnO-TOCN with the same antibacterial content prepared by the in-situ deposition method. Antioxidant activity tests in vitro showed that TS-TOCN had a significant scavenging effect on DPPH (2,2-Diphenyl-1-picrylhydrazyl) radicals. This design strategy makes it possible for inexpensive and abundant Camellia oleifera remainders to be widely used in the field of biobased materials.

Optimized method of thermoelectric cooler-based thermal management for improving the luminous efficacy of light-emitting diodes

We experimentally performed a method of active cooling for white LED that can reduce the temperature of the LED by using TEC for reducing the temperature of the LED board. The relation of LED board and input power for TEC was investigated to find out the optimized curve of LED board temperature and input power for TEC. Also, the TEC based cooling system was applied for RGBW LEDs. The obtained result is meaningful in LED thermal management, improving the lighting quality and increases the lifespan for both middle and high-power LED types. Full Text: PDF References E.F. Schubert, J.K. Kim, "Solid-State Light Sources Getting Smart", Science, 308, 1274 ¬(2005). CrossRef Q.K. Nguyen, "Emission spectrum modeling of white LEDs light source with using Gaussian function", Photonics Lett. Pol.,15(4), 54 (2023). CrossRef C.C. Sun, S.H. Ma, Q.K. Nguyen, "Advanced LED Solid-State Lighting Optics", Crystals, 10, 758 (2020). CrossRef S.P. Ying, H.K. Fu, W.F. Tang, R.C. Hong, "The Study of Thermal Resistance Deviation of High-Power LEDs", IEEE Trans. Electron Devices, 61, 2843 (2014). CrossRef K. Górecki, P. Ptak, "Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB", Energies, 14, 1286 (2021). CrossRef C.C. Sun, Q.K. Nguyen, T.X. Lee, S.K. Lin, C.S. Wu, T.H. Yang, Y.W.Yu. "Active thermal-fuse for stopping blue light leakage of white light-emitting diodes driven by constant current", Sci. Rep. 12, 12433 (2022). CrossRef Q.K. Nguyen, B. Glorieux, G. Sebe , T.H. Yang, Y.W. Yu , C.C. Sun, "Passive anti-leakage of blue light for phosphor-converted white LEDs with crystal nanocellulose materials", Sci Rep. 13, 13039 (2023). CrossRef N. Bădălan (Drăghici), P. Svasta, C. Marghescu, "A Method for Improving an Active Cooling Solution for LEDs ", IEEE 24th International Symposium for Design and Technology in Electronic Packaging (SIITME), Iași, Romania (2018). CrossRef A. Fan, R. Bonner, S. Sharratt, Y.S. Ju, "An innovative passive cooling method for high performance light-emitting diodes", 28th Annual IEEE Semiconductor Thermal Measurement and Management Symposium (SEMI-THERM), 319-324 (2012). CrossRef D.W. Kim, E. Rahim, A. Bar-Cohen, B. Han, "Direct Submount Cooling of High-Power LEDs", Compon. Packag. Technol., 33, 698 (2010). CrossRef N. Guan, N. Amador-Mendez, A. Kunti, A. Babichev, S. Das, A. Kapoor, N. Gogneau, J. Eymery, F.H. Julien, C. Durand, M. Tchernycheva, "Heat Dissipation in Flexible Nitride Nanowire Light-Emitting Diodes", Nanomater, 10, 2271 (2020). CrossRef S. Li, J.L. Liu, L. Ding, J.X. Liu, J. Xu, Y. Peng, M.X. Chen, "Active Thermal Management of High-Power LED Through Chip on Thermoelectric Cooler", IEEE Trans. Electron Devices, 68, 1753 (2021). CrossRef G.R. Sui, J.J. Chen, H. Ni, Y.Y. Ma, X.M. Gao, N. Wang, "Improvement of LED Performance With an Integrated Thermoelectric Cooling Package", IEEE Access, 8, 116535 (2020). CrossRef

Methods for Fabrication of Freestanding Nanocellulose Film as a Sustainable Material for Packaging and Biomedical Applications: A Review

Biopolymers are a sustainable alternative to traditional plastics in the medical and packaging fields. Biopolymers are biodegradable and can be used to reduce plastic pollution. They are derived from renewable resources like cornstarch, sugarcane, or cellulose. Cellulose nanomaterials have the potential to revolutionize various industries. However, the production process of nanocellulose films is time-consuming, and there is a need for quick and adaptable methods to fabricate these films. Techniques such as solvent casting, spin coating, roll-to-roll printing, layer-by-layer assembly, vacuum filtration, and spraying are used to fabricate free-standing nanocellulose films, each with its advantages and limitations. The spraying process shows promise in producing nanocellulose films quickly and efficiently. In addition to that, the need for free-standing nanocellulose films in medical packaging and tissue engineering areas was admirable. However, the rapid process for fabrication of the film should be developed for large-scale production and commercialization of films.