Cellulose Nanocrystals Research Articles

Biogas purification using cellulose nanocrystals/polyvinyl alcohol coated facilitated transport hollow fiber membranes with L‐arginine as CO2 carrier

AbstractThe composition of biogas consists mainly of CH4 (~60%) and CO2 (40%). To be considered a clean fuel, CH4 concentration in biogas must be increased to over 95%. In this study, membranes which were stacked in a chamber were utilized to purify biogas by passing biogas over them. These membranes were composed of polyethersulfone hollow fiber substrate coated with a “selective layer” made of cellulose nanocrystals (CNC‐0–2 wt) in polyvinyl alcohol (PVA) and l‐arginine as a CO2 carrier. Of the different CNC concentrations in PVA‐LA, CNC1/PVA‐LA (1.0 wt% CNC in PVA‐LA) displayed the lowest water contact angle of 17° (corresponding to higher moisture absorbing ability). With further increase in CNC concentration, even though CNC1.5/PVA‐LA showed the higher crystallinity (66%), and water contact angle increased (20°); reducing the chances of facilitated transport of CO2 through it. Biogas separation experiments were conducted at 90% RH and different feed pressures (0.8–1 bar) for various CNC concentrations. Increasing the CNC concentration led to a thicker selective layer, enhancing the CO2 permeability and selectivity up to CNC1/PVA‐LA. However, with the further addition of CNC, both permeability and selectivity decreased. At 90% RH and 1 bar feed pressure, the CNC1/PVA‐LA setup demonstrated a CO2 permeability of 20,522 Barrer and a selectivity of 33, making it suitable for low‐pressure biogas storage systems with lower energy requirements.

Cutting Edge Nanoplatforms with Smart Bio-sensing Applications: Paving the Way for Sustainable Green Approaches

Abstract: In the era of automation, sustainable technologies employing eco-friendly materials and manufacturing techniques such as ‘Green nanobiosensors’ have taken centre stage, owing to their opulent portfolio encompassing renewable fabrication and design from biomaterials, biocompatibility, and ease of functionalization. Generally, sensors utilize nanomaterials sourced from renewable resources or with minimal environmental impact, such as cellulose nanocrystals, chitosan, and biopolymers, owing to their exceptional properties such as high surface area. With the advent of environmentally conscious attributes in the cutting-edge nano biosensing technology, green nano-biosensors offer innovative avenues for sensitive and selective detection and monitoring of myriad analytes with minimal environmental repercussions. Further, such sensors operate at low energy levels, contributing to reduced energy consumption, and can be mass-produced with minimal environmental influence. The present outlay of literature aims to decipher the utilization of eco-friendly materials and sustainable manufacturing techniques in creating nano-biosensors and subsequently promulgating their advantages in terms of energy efficiency, low environmental impact, and use of renewable resources. Furthermore, this study embellishes a comprehensive framework that delineates the diverse applications of these green nanobiosensors as eco-friendly technological solutions across diverse sectors primarily agriculture, environmental monitoring, and biomedicine, showcasing their potential to revolutionize these domains while minimizing environmental impact.

Modern developments in lasing with liquid crystals

A review of the recent developments in the field of lasing with liquid crystals (LCs) is presented. After an introduction into the principle of lasing the different relevant liquid crystal phases to the field are introduced, namely, the nematic and chiral nematic phase, Blue Phases, twist grain boundary and ferroelectric liquid crystals. The classic examples of liquid crystal lasing are shortly discussed, together with a variety of possibilities for tuning the lasing wavelength, before the modern trends in LC lasing are discussed in detail. These are particularly random lasers, where the effects of nanoparticles, quantum dots and solitons are highlighted, as well as localized surface plasmon resonance. Other modern laser systems that have attracted recent interest, white lasers, whispering gallery mode lasers and those with biological materials, for example, cellulose nanocrystals, are also introduced and the latest developments outlined.

Study on Surface Esterification of Cellulose Nanocrystals Their and Lipid-Lowering Effect

ABSTRACT With the rapid development of the economy and changes in dietary structure, there is an excessive intake of high sugar and high-fat foods. To address this issue, in this study, we grafted palmitic acid onto CNC in the form of ester groups and evaluated its adsorption performance. Research had found that among these three methods, the CDI catalytic method can successfully obtain esterification modified CNC while also taking into account its environmentally friendly and pollution-free characteristics. Compared with CNC, its adsorption capacity for oil had increased, with the maximum adsorption capacity increasing from 35.80 g/g to 46.91 g/g. Meanwhile, the degree of esterification substitution of esterification modified CNC was measured, and the result was 0.03. Especially, after adding CNC-PA, the hydrolysis of fat was significantly reduced during the simulated digestion in vitro, whilst the absorption of fat in the intestine was significantly inhibited. In vivo testing also confirmed that consuming a diet containing CNC-PA significantly reduced elevated levels of triglycerides (TG) compared to the high-fat control group while long-term feeding of a diet containing CNC-PA reduced weight and fat accumulation.

Valorization of water hyacinth: Efficient extraction of nanofibrillated crystals using ultrasound-assisted TEMPO oxidation and their application in flexible piezoelectric films

This study presents an efficient extraction of nanocellulose crystals (CNCs) and nanofibers (CNFs) through ultrasound-assisted TEMPO oxidation method using deep-processed heavy metal-containing calabash as raw material. The extraction method, integrating TEMPO-mediated oxidation and ultrasound techniques, enhanced the yield of CNCs and CNFs. The results demonstrate that CNCs yielded 63 %, with a carboxyl content of 1.27 mmol/g, while CNFs yielded 31 %, with a carboxyl content of 1.21 mmol/g. CNCs and CNFs exhibited excellent mechanical properties, with CNCs having an average length of 214.4 nm, average diameter of 2.72 nm, and a length-to-diameter ratio of 78.8. CNFs had an average length of 437.8 nm, average diameter of 5.7 nm, and a length-to-diameter ratio of 76.8. X-ray diffraction (XRD) results showed crystallinity of 87.1 % for CNCs and 81.2 % for CNFs. The thermal stability of the fibers was confirmed up to 230℃. The film prepared by combining 10 % PVA with 90 % CNC exhibited a tensile strength of 32.11 MPa, Young's modulus of 2027.1 MPa, and could generate a maximum voltage of 0.83 V. This study provides an effective pathway for the value-added utilization of deep-processed calabash and highlights the broad application prospects of the composite film in the field of flexible sensors.

Rational design of pH-responsive nano-delivery system with improved biocompatibility and targeting ability from cellulose nanocrystals via surface polymerization for intracellular drug delivery

Cellulose nanocrystals (CNCs), derived from diverse sources and distinguished by their inherent biodegradability, excellent biocompatibility, and facile cellular engulfment due to their rod-like structure, hold great promise as carriers for the development of nano-delivery systems. In this work, highly efficient rod-like CNCs were employed as substrates for grafting glycidyl onto their surfaces through ring-opening polymerization, forming hyperbranched polymers with superior cell uptake properties. Subsequently, 4-vinylbenzeneboronic acid (VB) and poly (ethylene glycol) methyl ether methacrylate (PEGMA) were employed as monomers in the polymerization process to fabricate a pH-responsive targeted nano-delivery system, denoted as CNCs-VB-PEGMA, via single electron transfer reactive radical polymerization (SET-LRP) reaction. The CNCs-VB-PEGMA was successfully prepared and used for the loading of curcumin (Cur) to form a pH-responsive nano-delivery system (CNCs-VB-PEGMA-Cur), and the loading rate of Cur was as high as 70.0 %. Studies showed that this drug delivery system could actively targeting liver cancer cells with the 2D cells model and 3D tumor microsphere model, showing efficient liver cancer cell-killing ability. Collectively, the CNCs-VB-PEGMA drug delivery system has potential applications in liver cancer therapy as an actively targeting and pH-responsive drug delivery system.

Efficient Isolation of Cellulose Nanocrystals from Seaweed Waste via a Radiation Process and Their Conversion to Porous Nanocarbon for Energy Storage System.

This article presents an efficient method for isolating cellulose nanocrystals (CNcs) from seaweed waste using a combination of electron beam (E-beam) irradiation and acid hydrolysis. This approach not only reduces the chemical consumption and processing time, but also improves the crystallinity and yield of the CNcs. The isolated CNcs were then thermally annealed at 800 and 1000 °C to produce porous nanocarbon materials, which were characterized using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy to assess their structural and chemical properties. Electrochemical testing of electrical double-layer capacitors demonstrated that nanocarbon materials derived from seaweed waste-derived CNcs annealed at 1000 exhibited superior capacitance and stability. This performance is attributed to the formation of a highly ordered graphitic structure with a mesoporous architecture, which facilitates efficient ion transport and enhanced electrolyte accessibility. These findings underscore the potential of seaweed waste-derived nanocarbon as a sustainable and high-performance material for energy storage applications, offering a promising alternative to conventional carbon sources.

Toward mechanical recyclability of high barrier food packaging films through filler incorporation on the EVOH layer

AbstractTo preserve food from moisture and oxygen, polymers, such as ethylene vinyl alcohol (EVOH) are used in multilayer structures to provide oxygen barrier, while low‐density polyethylene (LDPE) is used for a water vapor barrier. While this material combination is functionally ideal, it may not comply with the new packaging recycling guidelines. Some European markets have implemented rules that limit the weight percentage of EVOH in LDPE films. One way to increase recyclability is by reducing the amount of EVOH in the film structure while maintaining the packaging's oxygen barrier properties. To achieve this, it is necessary to improve the barrier properties of EVOH. With this objective in mind, this study evaluated the incorporation of nanoclays (NC), cellulose microcrystals (MCC), silicon dioxide nanoparticles (SiO2), and cellulose nanocrystals (CNC) into an EVOH matrix. The results indicate that NC and MCC facilitate a stable blown film extrusion process and have a better dispersion in the EVOH matrix. Based on this finding, three‐layer films (with an ABA configuration) consisting of LDPE (A) and EVOH (7 μm layer) with 0.5 or 1 wt.% MCC or NC (B) were produced to protect the EVOH from moisture and enable blown film processing. The oxygen transmission rate (OTR) values were lowest for 0.5 wt.% NC and 1 wt.% MCC incorporation. Although the films with micro and nanoparticles had increased haze, this did not affect the visibility of the packaged food.

Rheology of nanocrystalline cellulose (CNC) gels: Thixotropy, yielding, wall slip, and shear banding

This study focuses on the rheological behavior of a cellulose nanocrystal gel. This system [5 wt. % cellulose nanocrystal (CNC) + 20 mM NaCl] is proved to be thixotropic, and the detected shear force tightly depends on the growth and break-up of the aggregates of CNC rods. From strain-controlled experiments, a nonmonotonic steady-state flow curve with a minimum stress value of ≈33 Pa is found, and the negative slope of stress versus shear rate suggests the existence of shear bands. From stress-controlled experiments (creep), the “static yield stress” is determined to be 67.5 ± 2.5 Pa. This difference proves that the local minimum stress of the flow curve does not coincide with the “static yield stress” determined by creep tests. However, this minimum stress can maintain flow provided that the material is already in a yielded state. At nominal shear rates below about 100 s−1, shearing is suggested to be localized in a shear band rather than over the whole material. The “dynamic yield stress” is found as “the minimum stress to maintain flow,” or the onset of shear banding. Moreover, wall slip also occurs at low nominal shear rates which is related to the interaction between the dynamic microstructure of the CNC gel and the wall: it is hypothesized that the low shear rates allow the CNC aggregates to extensively grow and, thus, the oversized CNC aggregates detach from the asperities of the wall. Our finding of the robust connection between yielding, thixotropy, wall slip, and shear banding shall shed new light on the nature of the nonmonotonic flow curves of yield stress and thixotropic materials.

Highly stable, controllable, and antibacterial nanocellulose-stabilized aroma emulsions via interfacial self-assembly strategy

The nanocellulose-stabilized aroma emulsions have the potential to replace surfactant-stabilized emulsions. However, the stability of aroma emulsions stabilized by nanocellulose still remains a challenging task. Herein, we developed a stable nanocellulose-stabilized aroma emulsion with controllable and antibacterial properties through cellulose nanocrystal (CNC) and NH2-PDMS-NH2 self-assembly at the oil-water interface. The stability, interfacial behavior, rheological and antibacterial properties of the emulsion were investigated. Our results reveal that the creaming index of the emulsions remained almost unchanged even after being stored for one week. The interfacial tension between the CNC aqueous phase and limonene decreased from 20.5 to 8.5 mN/m, as the addition of NH2-PDMS-NH2 (20 mg/mL). Notably, the interface tension (ranging from 3.5 to 11.1 mN/m) and the interfacial coverage rate of the CNC at the oil/water interface (ranging from 68.6 % to 97.5 %) could be tune by adjusting the pH value of the aqueous phase. The storage modulus and viscosity of the emulsions increased as the concentration of NH2-PDMS-NH2 increased. The aroma emulsion was highly stable under the conditions of 1.5 wt% CNC, 10 mg/mL NH2-PDMS-NH2, the oil/water ratio of 1/9, and the aqueous phase pH of 3. Moreover, these emulsions exhibited significant resistance to Escherichia coli and Staphylococcus aureus. Overall, this research provides a method to prepare a stable nanocellulose-based aroma emulsion, which could extend the application area of aroma emulsion.

Cellulose Nanocrystal-in-Solvent Processing for Efficient One-Pot Upcycling of Commercial Polymeric PFAS.

Upcoming regulations aim to ban per- and polyfluoroalkyl substances (PFAS), including commercial polymeric PFAS, or fluoropolymers, such as poly(tetrafluoroethylene) (PTFE) and poly(vinylidene fluoride) (PVDF), due to their environmental and toxicological impacts. However, fluoropolymers also provide crucial properties for clean energy transitions, and their regulation may hinder further technological advancements. Therefore, a facile one-pot recycling-upcycling strategy for fluoropolymers using inexpensive biomass, such as cellulose nanocrystals (CNCs), as absorbents and cocomponents for fluoro-functionalized composites could align with global sustainability goals and technological demands. Herein, we present a closed-loop CNC-in-solvent (CiS) processing system, which involves stirring fluoropolymers and CNCs in only low-polarity solvents like toluene (CiS-T). Our study reveals that CiS-T is a two-step process where the CNC-solvent interaction exposes CNCs' reducing end aldehyde protons due to solvent polarity and promotes H-F bond formation. The solvent used was recollected and reused. Additionally, we demonstrate the practical application of PTFE- and PVDF-CNC hybrids, byproducts of the CiS-T process, as performance-enhancing agents in green-energy-harvesting devices such as triboelectric nanogenerators. Our findings not only offer a sustainable method to overcome challenges from regulations against commercial fluoropolymers but also offer insights into developing an efficient, solvent-mediated CNC functionalization process that addresses forthcoming challenges in key industries.

Valorizing Biopolyester Suberin: Modification of Cellulose Nanocrystals and Performance Assessment in 3D-Printed Biobased Acrylates.

Suberin, a common biomass processing waste, is a complex biopolymer and a promising source for the biorefinery of chemicals. Six different approaches for the extraction of birch outer bark suberin fatty acids (SFAs) were explored, and their application in grafting the surface of cellulose nanocrystals (CNCs) was investigated. Successful CNC functionalization was controlled with FTIR and NMR analyses. In-depth research allowed us to evaluate the interface of the nanocellulose and polymer matrix. Three structurally distinct SFA-grafted CNCs were integrated into a vegetable oil-based acrylate resin in an ultralow concentration of 0.1 wt %. Five biobased acrylic resin formulations were prepared: without reinforcement, with CNC, and with three distinct SFA-grafted CNCs. Vat photopolymerization (VP) 3D printing was utilized for sample preparation. The effects of grafted CNC components on 3D-printed samples' thermal stability, thermomechanical properties, and wettability were evaluated in detail. CNC functionalization enhanced the interface with the polymer matrix, yielding up to a 2-fold increase in elongation and up to a 2.5-fold increase in strength in tensile and flexural tests compared to the polymeric matrix. The CNC-SFA-modified filler demonstrated performance comparable to, or even better than, petroleum-based chemical modification routes found in the existing literature. This study highlights a promising approach for green functionalization of CNCs and verifies its use in interface enhancement using a biobased acrylate matrix.

Structural evolution and stabilisation mechanism of foam fluids that contain cellulose nanofibres and cellulose nanocrystals: An experimental and theoretical study

Foam fluids are thermodynamically metastable systems, and they evolve over timescales comparable to their time of use, which makes the study of their destabilisation mechanisms crucial for many industrial applications. In our study, foams were made from fluids that contained cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs). We explored the effects of nanocelluloses and oils (n-heptane and n-dodecane) on foam stability, bubble coarsening and liquid drainage. Results show that the evolution of the bubble size is strongly slowed by the synergistic effect of CNCs and CNFs, and the structural evolution of foam is greatly impacted. The main responsible mechanism is an increase in local yield stresses due to the presence of CNCs in the foam. The jammed CNCs in foam produce a drainage delay, which makes the foam 50 % drainage time (t50%) of the experimental value deviate by up to 400 % from the classical theory value. When the bubbles coarsen and grow above a threshold size, liquid can drain out of the foam. Finally, a modified model for t50% that considers the drainage delay was proposed. The experimental results validated the proposed correlation and exhibited good reliability and predictive accuracy. The results enable us to elucidate the impact of CNCs and CNFs on the stability of foam fluids.

Mechanical Performance of Cellulose Nanocrystal and Bioceramic-Based Composites for Surgical Training.

This study evaluated the mechanical performance of a cellulose nanocrystal (CNC)-based composite, consisting of hydroxyapatite and natural fibers, mimicking the mechanical properties of real bone. The effect of natural nanofibers on the cutting force of the composite was evaluated for suitability in surgical training. Although hydroxyapatite has been extensively studied in bone-related applications, the exploration of epoxy-based composites incorporating both hydroxyapatite and CNC represents a novel approach. The evaluation involved a load cell with an oscillating saw. The uniform distribution of CNCs within the composite was assessed using 3D X-ray imaging. The cutting force was found to be 4.005 ± 0.5469 N at a feed rate of 0.5 mm/s, comparable to that required when cutting real bone with the osteon at 90°. The 90-degree orientation of the osteon aligns with the cutting direction of the oscillating saw when performing knee replacements on the tibia and femur bones. The addition of CNCs resulted in changes in fracture toughness, leading to increased material fragmentation and surface irregularities. Furthermore, the change in the cutting force with depth was similar to that of real bone. The developed composite material enables bone-cutting surgeries using bioceramics and natural fibers without the risks associated with cadavers or synthetic fibers. Mold-based computed tomography data allows for the creation of various bone forms, enhancing skill development for surgeons.

Chiral Nematic Cellulose Nanocrystal Films for Enhanced Charge Separation and Quantum-Confined Stark Effect.

Efficient charge separation is essential in various optoelectronic systems, yet it continues to pose substantial challenges. Building upon the recent evidence that chiral biomolecules can function as electron spin filters, this study aims to extend the application of chirality-driven charge separation from the molecular level to the mesoscale and supramolecular scale. Utilizing cellulose nanocrystals (CNCs) derived from cellulose, the most abundant biomaterial on Earth, this research leverages their self-assembly into chiral nematic structures and their dielectric properties. A device is introduced featuring a chiral nematic hybrid film composed of CNCs and quantum dots (QDs), decorated with iron oxide nanoparticles. Using the quantum-confined Stark effect (QCSE) to probe charge separation, we reveal significant sensitivity to the circular polarization of light and the chiral nematic structure of the film. This approach achieves effective, long-lasting charge separation, both locally and across length scales exceeding 1 μm, enabling potential applications such as self-assembled devices that combine photovoltaic cells with electric capacitance as well as optical electric-field hybrid biosensors.

Inverse Pickering emulsion stabilized by modified cellulose nanocrystals for drilling fluid application

With the rise in oil consumption, the production and exploration of oil have increasingly targeted unconventional reservoirs. Oil-based drilling fluids (ODFs) are well-suitable for unconventional reservoirs because of their superior wellbore stability, strong lubrication, and great resistance to contamination. Inverse (water-in-oil, W/O) emulsions have the ability to lower the oil content in conventional ODFs through the addition of water, leading to more cost-effectiveness and eco-friendliness. However, inverse emulsions require the introduction of a large amount of surfactants to stabilize the oil/water interface, which led to environmental pollution. To address these issues, surface modified cellulose nanocrystals (C14-CNCs) were prepared through acylation modification and then used as solid stabilizers to prepare a high-performance inverse Pickering emulsion-based drilling fluid (IPEDF), in which sunflower seed biodiesel was chosen as the oil phase, and organobentonite (i.e., low polarity SD-1 and high polarity SD-2) was used as a viscosifier and filtration loss reducer. The stability and structure of Pickering emulsion can be controlled by altering the hydrophilicity of C14-CNCs through adjusting the reaction time of acylation. Through optimization of the polarity of organobentonite and the hydrophilicity of C14-CNCs, the as-formulated IPEDF exhibits superior shear-thinning behavior, thixotropy, and filtration property. This work provides a promising avenue for using biomass-derived nanomaterials as stabilizers for the high-performance inverse Pickering emulsion drilling fluids.

Cellulose nanocrystal extraction from tissue paper wastes using different extraction methods and cellulose acetate production

ABSTRACT This paper examines the feasibility of extracting cellulose from tissue paper wastes (TPW’s) using several methods: sonication (SC), subcritical (SU), microwave (MC), and microwave with diluted acid (MA). The chemical characterisation and morphological properties of nanocrystal cellulose were investigated using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and scanning electron microscopy with energy dispersive X-Ray analysis (SEM-EDX). TPW’s have a relatively high crystallinity index (CrI = 61.02%). It was found to be lower than that for cellulose extracted using SU and SC MC, MA methods, where CrI to 65.65%, 68.07%, 69.21% and 73.42%, respectively. The MA method yielded cellulose with the highest CrI and altered surface morphology. This cellulose was selected for cellulose acetate synthesis. After acetylation, the CrI decreased to 61.45%, and the morphological aspect was changed. In conclusion, nanocrystal cellulose was successfully extracted from TPW’s and effectively changed to its esterified form.

Recent research progress on hairy cellulose nanocrystals: Preparation and applications

Recent research progress on hairy cellulose nanocrystals: Preparation and applications

Hydroxyapatite-Carboxylated Cellulose Nanocrystals and Urea: Effects on Nitrogen Management and Tomato Growth

Hydroxyapatite-Carboxylated Cellulose Nanocrystals and Urea: Effects on Nitrogen Management and Tomato Growth

Cellulose nanocrystal (CNC) from okra plant (Abelmoschus esculentus L.) stalks as a reinforcement in bionanocomposite fabrication: Extraction, processing, and characterization study

Currently, CNC is attractive to the researchers to fabricate multifunctional bionanocomposite because of their outstanding physicochemical, thermomechanical, morphological properties, and eco-friendly nature. Whereas in most cases CNC is extracted from the bast/bark of primary plants, which have other beneficial applications in several sectors. Hence, it is crucial to find out alternative sources of CNCs to diminish the extra pressure on the primary plants. While the useless agrowaste biomass of okra stalks would be a new and beneficial alternative to produce CNCs as a reinforcement. Here, a series of chemical reactions were directed to produce CNCs. The samples were characterized by FTIR-ATR,TGA/DTA,FESEM,EDX,XRD,UV–vis-NIR, and DLS analysis. The obtained results suggested that the newly produced CNCs possessed substantial active functional groups(–OH,CO-C,–NH), high thermal stability, greater crystallinity(86.09±0.001 %), and notable microstructure indicating a well-organized porous surface with encouraging spherical shapes. The CNCs are free from impurities and coloring materials; additionally, they exhibit a highly negative surface charge and smaller particle sizes. It can be stated that the produced CNCs should have a good agreement with the sustainable environment and be beneficially applied as a reinforcing agent to fabricate bionanocomposites. Also acts as a sustainable alternative to the fossil-based hazardous ones for various uses.