Search Results (682)

The present study focuses on the effect of doping KH560-modified cellulose nanocrystals (CNCs) on the electro-optical characteristics of polymer-dispersed liquid crystals (PDLCs). PDLC films were fabricated through the polymerization-initiated phase separation (PIPS) process and doped with CNC nanoparticles at various concentrations. At low concentrations, the CNCs at the interface, by virtue of their unique chiral characteristics, induce an orderly arrangement of liquid crystal molecules. Meanwhile, the interaction between the film’s fiber structure and the liquid crystal droplets brings about an augmentation in the arrangement efficiency. The excellent dispersion of CNCs diminishes the random alignment of liquid crystal molecules and mitigates light scattering. Additionally, it aids in the deflection of the liquid crystal director, facilitating the lubrication of the liquid crystals’ movement. It is remarkable that within the range of relatively lower CNCs doping concentrations, specifically from 0.005 wt% to 0.05 wt%, the PDLC films exhibit lower threshold and saturation voltages, faster response, enhanced viewing angle performance and higher contrast. Full article

In this study, we report an effective, one-step chemical treatment to directly isolate carboxylated cellulose nanocrystals (CCNCs) from a lignocellulosic source using a mixture of peracetic acid and 10% H₂SO₄ solution. We used infrared spectroscopy, X-ray diffraction, dynamic light scattering, atomic force microscopy, and scanning electron microscopy to characterize all the materials. The obtained CCNCs exhibited needle-like shapes with a width of 10–50 nm and a length of 200–500 nm, a high crystalline index (71.3%), and a high content of -COOH groups (~1.405 mmol/g), with a zeta potential value of −48.5 mV. We attributed this to the cooperative effect of strong oxidative agent and strong acid, which makes the removal of all components occur simultaneously in parallel with the partial hydrolysis of amorphous cellulose regions. Our study opens a new, simple approach to directly isolate cellulose nanocrystals from a lignocellulosic source. Full article

Developing multifunctional wound dressings with excellent mechanical properties, strong tissue adhesion, and efficient antibacterial activity is crucial for promoting wound healing. This study prepared a novel nanocomposite hydrogel dressing based on sodium alginate-polyacrylic acid dual crosslinking networks, incorporating tannic acid-coated cellulose nanocrystals (TA@CNC) and in-situ reduced silver nanoparticles for multifunctional enhancement. The rigid CNC framework significantly improved mechanical properties (elastic modulus of 146 kPa at 1 wt%), while TA catechol groups provided excellent adhesion (36.4 kPa to pigskin, 122% improvement over pure system) through dynamic hydrogen bonding and coordination interactions. TA served as a green reducing agent for uniform AgNPs loading, with CNC negative charges preventing particle aggregation. Antibacterial studies revealed synergistic effects between TA-induced membrane disruption and Ag⁺-triggered reactive oxygen species generation, achieving >99.5% inhibition against Staphylococcus aureus and Escherichia coli. The TA@CNC-regulated porous structure balanced swelling performance and water vapor transmission, facilitating wound exudate management and moist healing. This composite hydrogel successfully integrates mechanical toughness, tissue adhesion, antibacterial activity, and biocompatibility, providing a novel strategy for advanced wound dressing development. Full article

To remove nickel (II) from an aqueous solution, cellulose nanocrystals (CNCs) were modified as an adsorbent. The FTIR and SEM were used to characterise the properties of CNCs. In addition to how well they predicted reaction (adsorption capacity), the central composite design was used. The response surface model method performs well, according to statistical data. Four operational variables were studied: The initial concentration of the nickel (II) solution in mg/L, the pH, the contact period in minutes, and the adsorbent dose in g/100 mL. The removal percentage (%) was the result. The percentage removal was 98% after 178 min of contact, a starting concentration of 110 mg/L, an adsorbent dosage of 9.3 g, and an initial pH of 3.5. The R² was 0.996, the adjusted R² was 0.921, and the predicted R² was 0.945. The quadratic equation was determined using central composite design. The FTIR examination revealed that the functional groups, hydroxyl groups (OH), peaked around 3300–3500 cm^−1, and carboxyl groups (COOH) peaked around 1700 cm⁻¹. Full article

Cellulose nanocrystals (CNCs) have attracted growing interest in optics and electronics, extending beyond their traditional applications. They are considered key materials due to their fast computing, sensing adhesion, and emission of circularly polarized luminescence with high dissymmetry factors. This interest arises from their unique chemical structure, which gives rise to structural color, a chiral nematic phase, and high mechanical strength. In this perspective, we first introduce the definition, sources, and fundamental properties of CNCs to explain the basis for their unique and effective use in optics and electronics. Next, we review recent research on the application of CNCs in these fields. We then analyze the current limitations that hinder further advancement. Finally, we offer our own perspective on future directions for the CNC-enabled advanced optics and electronics. Full article

Microbial contamination is a global concern with impacts on a variety of industries ranging from marine to biomedical applications. Recent research on hydrophilic polymer-based coatings is focused on combining antifouling polymers with nanomaterials to enhance mechanical, optical, and stimuli-responsive properties, yielding colour changing, self-healing, and super hydrophilic materials. This study combines the hydrophilic and antifouling properties of vitamin B5 analogous methacrylamide (B5AMA)-based polymers with stimuli-responsive anthocyanin-dye-loaded cellulose nanocrystals (CNCs) to develop antifouling materials with colour changing capabilities upon bacterial contamination. Poly(B5AMA)-grafted CNCs were prepared through surface-initiated photoiniferter reversible addition fragmentation chain transfer (SP-RAFT) polymerization and characterized through proton nuclear magnetic resonance (¹H-NMR), transmission electron microscopy (SEM/TEM), and X-ray photon spectroscopy (XPS) to confirm the formation of surface-grafted polymer chains. The bare CNCs and poly(B5AMA)-grafted CNCs were loaded with anthocyanin dye and evaluated for pH-dependent colour changing capabilities. Interestingly, anthocyanin-loaded CNCs demonstrated vibrant colour changes in both solution and dried film form upon bacterial contamination; however, limited colour changing capabilities of the composites, specifically in dried film form, were attributed to the enhanced dispersibility and antifouling capabilities of the polymer-coated CNCs. Full article

This study investigates the combined use of electron beam irradiation (EBI) and nanotechnology to develop improved food packaging films. EBI, commonly applied for sterilization, can alter polymer microstructure, while irradiated cellulose nanocrystals (CNCs) offer enhanced functionality when incorporated into biopolymer matrices. Here, CNCs were irradiated with doses up to 50 kGy, leading to the formation of carboxyl and aldehyde groups, confirmed by FTIR analysis, as a consequence of the initial formation of free radicals and peroxides that may subsist in that original form or be converted into various carbonyl groups. Flexible films were obtained by incorporating pristine and EB-irradiated CNCs in an internal mixer, using minute amounts of poly(ethylene oxide) (PEO) to facilitate the dispersion of the filler within the polymer matrix. The resulting PLA/PEO/CNC films were evaluated for their mechanical, thermal, barrier, and antioxidant properties. The results showed that structural modifications of CNCs led to significant enhancements in the performance of the composite films, including a 30% improvement in water barrier properties and a 50% increase in antioxidant activity. These findings underscore the potential of irradiated CNCs as effective additives in biopolymer-based active packaging, offering a sustainable approach to reduce dependence on synthetic preservatives and potentially extend the shelf life of food products. Full article

This study presents the first quantitative comparison of catastrophic phase inversion behavior of water-in-oil emulsions stabilized by nanocrystalline cellulose (NCC) and molecular surfactants with different headgroup charge types: anionic (sodium dodecyl sulfate referred to as SDS), cationic (octadecyltrimethylammonium chloride referred to as OTAC), nonionic (C12–14 alcohol ethoxylate referred to as Alfonic), and zwitterionic (cetyl betaine referred to as Amphosol). By using conductivity measurements under controlled mixing and pendant drop tensiometry, this study shows that NCC markedly delays catastrophic phase inversion through interfacial jamming, whereas surfactant-stabilized systems exhibit concentration-dependent inversion driven by interfacial saturation. Specifically, NCC-stabilized emulsions exhibited a nonlinear increase in the critical aqueous phase volume fraction required for inversion, ranging from 0.253 (0 wt% NCC) to 0.545 (1.5 wt% NCC), consistent with enhanced resistance to inversion typically associated with the formation of rigid interfacial layers in Pickering emulsions. In contrast, surfactant-stabilized systems exhibited a concentration-dependent inversion trend with opposing effects. At low concentrations, limited interfacial coverage delayed inversion, while at higher concentrations, increased surfactant availability and interfacial saturation promoted earlier inversion and favored the formation of oil-in-water structures. Pendant drop tensiometry confirmed negligible surface activity for NCC, while all surfactants significantly lowered interfacial tension. Despite its weak surface activity, NCC imparted strong coalescence resistance above 0.2 wt%, attributed to steric stabilization. These findings establish distinct mechanisms for governing phase inversion in particle- versus surfactant-stabilized systems. To our knowledge, this is the first study to quantitively characterize the catastrophic phase inversion behavior of water-in-oil emulsions using NCC. This work supports the use of NCC as an effective stabilizer for emulsions with high internal phase volume. Full article

The efficient use of renewable lignocellulosic biomass has attracted wide interest, as it promises to reduce the environmental impact of fossil fuel consumption. A recently developed batch-scale process, which produces glycol lignin (GL) from softwood biomass, generates a considerable amount of cellulose-rich solid residues (SRs) as a byproduct. In this study, usable cellulose was isolated from SRs in the form of carboxylated cellulose nanocrystals (O-CNCs). The properties of O-CNCs were investigated to establish a possible integrated biomass utilization system based on the GL production technology. Three different forms of purified SRs—never-dried (N-Cel), freeze-dried (F-Cel), and vacuum-dried (V-Cel) cellulose—were subjected to oxalic acid (OA) hydrolysis at 95 °C for 4 h. The average length of O-CNCs ranged from 90 to 120 nm and the height ranged from 3 to 6 nm for separate particles and from 8 to 20 nm for aggregates. The carboxyl group content was 0.11–0.23 mmol/g O-CNCs. The overall results indicated that the yields, dimensions, surface charges, and thermal stability of the O-CNCs were largely influenced by the nature of the starting cellulose. In addition, O-CNCs prepared from recycled OA exhibited similar properties to those prepared from fresh OA. Full article

Bio-nanocomposites based on poly (vinyl alcohol) (PVA) and cellulosic nanostructures are favorable for active food packaging applications. The current study systematically investigates the mechanical properties, gas permeation, and swelling parameters of PVA composites with cellulose nanocrystals (CNC) or nano lignocellulose (NLC) fibers. Alterations in these macroscopic properties, which are critical for food packaging applications, are correlated with structural information at the molecular level. Strong interactions between the fillers and polymer host matrix were observed, while the PVA crystallinity exhibited a maximum at ~1% loading. Finally, the orientation of the PVA nanocrystals in the uniaxially stretched samples was found to depend non-monotonically on the CNC loading and draw ratio. Concerning the macroscopic properties of the composites, the swelling properties were reduced for the D1 food simulant, while for water, a considerable decrease was observed only when high NLC loadings were involved. Furthermore, although the water vapor transmission rates are roughly similar for all samples, the CO₂, N₂, and O₂ gas permeabilities are low, exhibiting further decrease in the 1% and 1–5% loading for CNC and NLC composites, respectively. The mechanical properties were considerably altered as a consequence of the good dispersion of the filler, increased crystallinity of the polymer matrix, and morphology of the filler. Thus, up to ~50%/~170% enhancement of the Young’s modulus and up to ~20%/~50% enhancement of the tensile strength are observed for the CNC/NLC composites. Interestingly, the elongation at break is also increased by ~20% for CNC composites, while it is reduced by ~40% for the NLC composites, signifying the favorable/unfavorable interactions of cellulose/lignin with the matrix. Full article

Here, we demonstrated a direct method to produce cellulose nanocrystals (CNCs) with a rod-like shape from microcrystalline cellulose by a ZnCl₂-based deep eutectic solvent (DES) with a high yield (~80.1%). We obtained CNCs, crystalline index (68.9%), with a width of ~30–50 nm and a length of 200–400 nm. Importantly, we were able to functionalize the CNCs with an acetyl, -(CO)CH₃, group, which could potentially modulate the hydrophobic property of the CNCs. We attributed the formation of the CNCs to the Lewis acid effect of ZnCl₂, which can hydrolyze the amorphous cellulose regime. Our study opens a new path to directly isolate cellulose nanocrystals with several functional groups on the surface of CNCs. Full article

Cellulose nanocrystals possess unique properties such as high surface area and excellent biocompatibility. They can disrupt strong hydrogen bonds and other intermolecular forces that hinder the solubility of certain molecules thus enhancing the solubility of poorly soluble materials. The main challenge in formulating poorly soluble drugs lies in their limited therapeutic efficacy due to inadequate solubility and bioavailability. Therefore, an innovative approach such as using cellulose nanocrystals to enhance the solubility is highly needed. The aim of this research is to study the potential of ramie (Boehmeria nivea L. Gaud) as a source of cellulose nanocrystals in the development of microspheres for the solubility enhancement of poorly soluble drugs. Nanocrystalline cellulose was isolated from the ramie (Boehmeria nivea L. Gaud) by optimizing hydrolysis conditions with varying acid concentrations and reaction times. Characterizations were performed by measuring particle size, pH, and sulfate content, followed by morphological study by SEM, functional group analysis, and thermal analysis. The use of sulfuric acid in the hydrolysis process of flax cellulose at 45 °C, as the type of acid that gives the best results, at 50% acid concentration for 60 min produces cellulose nanocrystallines with a particle size of 120 nm, sulfate concentration density of 133.09 mmol/kg, crystallinity of 96.2%, and a yield of 63.24 ± 8.72%. Furosemide was used as the poorly soluble drug model and its solubility enhancement in the form of furosemide/RNCC microspheres was evaluated through saturated solubility testing and in vitro dissolution. This study demonstrated that RNCC could improve the solubility of furosemide, which contributes to developing sustainable drug formulations and eco-friendly delivery systems for poorly soluble drugs. Full article

Cacao is a food of global interest. Currently, the industry primarily utilizes the seed, which represents between 21% and 23% of the total fruit weight. In 2023, global production reached 5.6 million tons of fermented dry cacao beans, while approximately 25.45 million tons corresponded to cacao residues. The objective of this review was to compile and analyze alternatives for the utilization of cacao by-products. The methodology involved technological surveillance conducted in specialized databases between 2015 and 2025. Metadata were analyzed using VOSviewer software version 1.6.20. Priority was given to the most recent publications in high-impact indexed journals. Additionally, 284 patent documents were identified, from which 15 were selected for in-depth analysis. The reviewed articles and patents revealed a wide range of industrial applications for cacao by-products. Technologies including ultrasonic and microwave-assisted extraction, phenolic microencapsulation, cellulose nanocrystal isolation and targeted microbial fermentations maximize the recovery of polyphenols and antioxidants, optimize the production of high-value bioproducts such as citric acid and ethanol, and yield biodegradable precursors for packaging and bioplastics. The valorization of lignocellulosic by-products reduces pollutant discharge and waste management costs, enhances economic viability across the cacao value chain, and broadens functional applications in the food industry. Moreover, these integrated processes underpin circular economy frameworks by converting residues into feedstocks, thereby promoting sustainable development in producer communities and mitigating environmental impact. Collectively, they constitute a robust platform for the comprehensive utilization of cacao residues, fully aligned with bioeconomy objectives and responsible resource stewardship. Full article

Cellulose nanocrystals (CNCs), derived from renewable biomass, have emerged as a pivotal component in the design of biomimetic composite hydrogels due to their exceptional mechanical strength, biocompatibility, and tunable surface chemistry. This review comprehensively explores recent advancements in surface modification strategies for CNCs (physical adsorption, chemical grafting, and bio-functionalization) and their impacts on the structure and properties of hydrogel networks, with particular emphasis on mechanical properties. Future applications in light/thermal/electrical-responsive soft actuators are critically analyzed. Guided by biomimetic design principles, the anisotropic mechanical responses induced by CNC-oriented alignment are explored, along with their cutting-edge advancements in soft robotics, wearable sensing, and biomedical devices. Perspectives are provided on future directions, including multi-stimuli synergistic actuation systems and sensing-actuation integration architectures. This work establishes a fundamental framework for designing CNC-enhanced smart hydrogels with tailored functionalities and hierarchical structures. Full article

Bio-based polydithioacetal nanocomposites were synthesized to address the critical need for materials that simultaneously achieve enhanced thermomechanical properties and excellent reprocessing capabilities. Using vanillin and cellulose nanocrystals (CNCs) as starting materials, linear polydithioacetals (PDTAs) were prepared via acid-catalyzed polycondensation of vanillin with various dithiols including 1,6-hexanedithiol, 1,10-decanedithiol, 3,6-dioxa-1,8-octanedithiol and 2,2′-thiodiethanethiol. These PDTAs were then crosslinked with a diepoxide (i.e., diglycidyl ether of bisphenol A, DGEBA) via the reaction of phenolic hydroxyl groups of PDTAs with epoxide groups of DGEBA. To create the nanocomposites, cellulose nanocrystals (CNCs) were surface-functionalized with thiol groups and then incorporated as the reinforcing nanofillers of the networks. The results of morphological observation showed that the fine dispersion of CNCs in the polymer matrix was attained. Owing to the incorporation of CNCs, the nanocomposites displayed improved thermomechanical properties. Compared to the network without CNCs, the nanocomposite containing 20 wt% CNCs exhibited an increase of more than tenfold in modulus and threefold in tensile strength. In addition, the nanocomposites exhibited excellent reprocessing properties, attributable to the dynamic exchange of dithioacetal bonds. This work presents a promising strategy for developing bio-based nanocomposites that have not only improved thermomechanical properties but also excellent reprocessing (or recycling) properties. Full article