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(a) Structural hierarchy of the cellulose fiber component from the tree to the anhydroglucose molecule (SEM image of wood cell structure: courtesy of D. Dupeyre, CERMAV); b) preparation of nanocrystals by selective acid hy‐ drolysis of the disorganized regions of cellulose microfibrils (TEM image of cotton CNCs: courtesy of CERMAV).
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Cellulose nanocrystals (CNCs) are high aspect ratio nanomaterials readily obtained from cellulose microfibrils via strong acid hydrolysis. They feature unique properties stemming from their surface chemistry, their crystallinity, and their three-dimensional structure. CNCs have been exploited in a number of applications such as optically active coa...
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... Technically, cell walls can be breakdown and various-sized components can be separated and harvested. Three representative sizes are cellulose fibrils (> 100 nm in diameter, > 200 μm in length) (f), cellulose nanofibrils (CNFs) (5-100 nm in diameter, 0.5-200 μm in length) (g), and cellulose nanocrystals (CNCs) (5-70 nm in diameter, < 500 nm in length) (h) [65]. Both CNFs and CNCs are also called nanocellulose. Figure 9. ...
... Figure 11. SEM morphology of membranes made from cellulose fibers (a) [75], fibrils (b) and nanofibrils (c) [76], nanocrystals (d) [65], electrospun nanofibers of cellulose acetate (e) [77] and regenerated cellulose (f) [78]. ...
Membranes are a selective barrier that allows certain species (molecules and ions) to pass through while blocking others. Some rely on size exclusion, where larger molecules get stuck while smaller ones permeate through. Others use differences in charge or polarity to attract and repel specific species. Membranes can be used to purify air and water by allowing only air and water molecules to pass through but preventing contaminants such as microorganisms and particles or to separate target gas or vapor, such as H2, CO₂, from other gases. The higher the flux and selectivity, the better a material is for membranes. The desirable performance can be tuned through material type (polymers, ceramics, and biobased materials), microstructure (porosity and tortuosity), and surface chemistry. Most membranes are made from plastic from petroleum-based resources, which contribute to global climate change and plastic pollution. Cellulose can be an alternative sustainable resource to make renewable membranes. Cellulose exists in plant cell walls as natural fibers, which can be broken down into smaller components such as cellulose fibrils, nanofibrils, nanocrystals, and cellulose macromolecules through mechanical and chemical processing. Membranes made from reassembling these particles and molecules have variable pore architecture, porosity, and separation properties and therefore have a wide range of applications in nano-, micro-, and ultrafiltration or forward osmosis. Despite their advantages, cellulose membranes face some challenges. Improving the selectivity of membranes for specific molecules often comes at the expense of permeability. The stability of cellulose membranes in harsh environments or under continuous operation needs further improvement. Research is ongoing to address these challenges and develop advanced cellulose membranes with enhanced performance. This article reviews the microstructure, fabrication methods, and potential applications of cellulose membranes, providing some critical insights into processing-structure-property relationships for current state-of-the-art cellulosic membranes that could be used to rationally improve their performance.
... Drying stage, particle arrangement, and substrate orientation are the elements that contributed to the agglomeration of nanocellulose in a TEM micrograph. In particular, the drying stage may cause aggregation and have an impact on the particles' subsequent redispersion [10,11]. In this study, the freeze drying of the CNS suspension is responsible for the agglomerated CNS particles. ...
Cellulose nanosphere (CNS) was isolated from corn husk by delignification, bleaching, acid hydrolysis, dialysis, and sonication. Successful isolation of CNS was confirmed by FTIR Analysis. The isolated CNS was found to have an average diameter of 18 nm and crystallinity index of 70% using TEM and XRD Analysis, respectively. A decrease in onset degradation temperature (Tonset) and an increase in residual mass were also observed in the TG analysis of cellulose fiber and CNS. Nanocomposite hydrogels using poly (ethylene glycol) dimethacrylate (PEGDMA) as matrix and CNS as nanofiller was prepared by UV-curing. FTIR Analysis revealed similar transmittance patterns among all the treatments. Thermal characterization showed that the addition of CNS lowers the Tonset and Tmax while increasing the temperature required for the total degradation of the UV-cured nanocomposite hydrogels.
... The fibrillation may be attributed to sulfonate anion (-OSO 3 − ) groups introduced on the cellulose composition. Despite the anionic charges on NCC fibrils inducing electrostatic repulsion among the microfibrils, the formation of hydrogen bonding between hydroxyl groups of the adjacent particles resulted in some agglomerations 22,23 . www.nature.com/scientificreports/ ...
Artemisia absinthium has long been used traditionally as an anti-microbial and antioxidant agent. Various biologically active secondary metabolites, including phenolic compounds such as gallic acid and p-coumaric acid, have been reported from the species. In addition, growing the plants under in vitro conditions enriched with elicitors is a cost-effective approach to enhance secondary metabolite production. This paper examined microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) effects on morphological characteristics, phenolic compounds, antioxidant activity, and volatile oil content of A. absinthium. The treated shoots with various concentrations of MCC and NCC were subjected to spectrophotometric, GC–MS, and LC–MS analysis. FESEM-EDX, TEM, XRD, and DLS methods were applied to characterize MCC and NCC properties. Morphological findings revealed that the stem length, dry, and fresh weights were improved significantly (P ≤ 0.05) under several MCC and NCC concentrations. Some treatments enhanced gallic and p-coumaric acid levels in the plant. Although 1.5 g/L of MCC treatment showed the highest antioxidant activity, all NCC treatments reduced the antioxidant effect. The findings suggest that both MCC and NCC, at optimized concentrations, could be exploited as elicitors to improve the secondary metabolite production and morphological properties.
... The transmission electron microscopy (TEM) characterization is the most popular among the nanoparticles [65][66][67]. With this analysis, the size and shape of the nanomaterials can be evaluated. ...
The bibliometric analysis by Methodi Ordinatio reveals the impressive increase in the published articles about green chemistry, and specificity in green synthesis of nanomaterials. In the last decade, they have published over 450 articles, most led by India, China, and Iran. The green synthesis is according to the 12 principles of green chemistry (PGCs) to obtain nanoparticles with minimization of waste and toxic emissions, use of green solvents and alternatives to conventional organic solvents, use of renewable and sustainable raw materials, and energy efficiency and use of renewable energy. After synthesis, the green nanoparticles are characterized to know their physical and chemical properties. Green synthesis can contribute to the sustainable development goals (SDGs) until nine goals can be associated with green synthesis and green nanoparticle applications. Among advantages and limitations, the green syntheses of nanoparticles have the potential to grow more by future perspectives gap.
... Furthermore, the combination of data from transmission electron and atomic force images was used to determine the optimal description of the morphology of the isolated nanocellulose. Transmission electron microscopy (TEM) could easily screen a large group of nanoparticlesproviding a clear view of nanocellulose size, shape, and uniformity -whereas atomic force microscopy (AFM) gives information on the particle thickness and patterns of nanocellulose dispersion on the surface (Zhu et al. 2011;Kaushik et al. 2015;Teixeira et al. 2015). ...
Nanocellulose is commonly isolated from cellulosic materials by chemical methods using strong acids. In this study, the enzymatic method was explored to isolate nanocellulose from commercial bleached S 2 grade abaca pulp. It was first disintegrated for 10 min and was subjected to enzyme hydrolysis while incubated with Bacillus sp. cellulase for 72 h at 50 °C and 120 revolutions/min. A clear liquid material was obtained after enzymatic hydrolysis after a series of centrifugation and ultrasonication. Results showed that the isolated nanocellulose had an average particle size of 375.9 nm ± 2.9 with a polydisperse index of 0.404 ± 0.059. Transmission electron and atomic force images showed that nanocellulose was longitudinal in size and highly aggregated and agglomerated. Through FTIR analysis, crystallinity indexes (i.e. lateral order index, total crystallinity index, and hydrogen bond intensity) of bleached abaca pulp and the isolated nanocellulose were compared. Results showed that the enzymatic hydrolysis of bleached abaca pulp resulted in higher cellulose crystallinity. Overall, nanocellulose can be isolated using biological methods using Bacillus sp. cellulase. These results could be used as a baseline to isolate smaller particle sizes, highly monodisperse, and stable nanocellulose that could be further applied in packaging, papermaking, cosmetics, medicine, and numerous other applications.
... BC was not chosen due to its high production cost. For NFC and NCC production, the fabrication methods involved the disintegration of plant cellulose using mechanical or chemical methods, while for BNC they involved the bioformation of cellulose by bacteria [53][54][55][56][57]. Figure 7 shows the comparison of nanocellulose in various applications. Next, the natural and synthetic fibers that are hybridized together were chosen under the design strategy of using the hybrid composition of natural and synthetic fibers to increase the composite strength and stiffness. ...
... Comparison of nanocellulose based on production methods and morphological structure[55][56][57][58][59][60]. ...
This research article elaborates on the conceptual design development of a sustainable bionanocomposite bracket for bracing installation in composite cross arm structures. The product design development employed the hybrid techniques of the theory of inventive problem solving (TRIZ), morphological chart, and analytic network process (ANP) methods. The current bracket design in the braced composite cross arm is composed of heavy and easy-to-rust steel material. Therefore, this research aims to develop a new bionanocomposite bracket design to replace the heavy and easy-to-rust steel bracket. This research also aims to implement a concurrent engineering approach for the conceptual design of bionanocomposite bracket installation to enhance the overall insulation performance. A preliminary process was implemented, which covered the relationship between the current problem of the design and design planning to build a proper direction to create a new design product using TRIZ. Later, the TRIZ inventive solution was selected based on the engineering contradiction matrix with specific design strategies. From the design strategies, the results were refined in a morphological chart to form several conceptual designs to select the ANP technique to systematically develop the final conceptual design of the bionanocomposite bracket for the cross arm component. The outcomes showed that Concept Design 1 scored the highest and ranked first among the four proposed designs. The challenges of the bionanocomposite bracket design for cross arm structures and the improvement criteria in concurrent engineering are also presented.
... This is often solved by calculating the equivalent spherical diameter of a cylinder. The advantage of DLS relies on its easiness and non-destructive character, but results are strongly influenced by physic-chemical features such as chemical composition, heterogeneity, topography, surface charge density, dispersing medium, viscosity, and also particle orientation (Kaushik et al. 2015). Considering that DLS results must be critically considered, Fig. 4 shows the average particle size determined by this technique as a function of the nanofiber length determined by TEM for the CNF fraction, as the latter measures the dimensions of the particles in the dry state, while DLS has the implications described above. ...
In this work, the efficiency of a polyelectrolyte complex (PEC) to retain different cellulose micro/nanofibers (CMNFs) during paper formation and to improve the physical properties of recycled unbleached fiber paper was analyzed. CMNFs were obtained from a commercial bleached eucalyptus pulp (BEP) using a PFI refiner followed by a chemical treatment with oxalic acid at two different concentrations. Finally, the pulp was fibrillated using a high-pressure homogenizer at three different intensities. The PEC was formed by addition of the xylan (Xyl) solution on chitosan (CH) solution with a Xyl/CH mass ratio of 80/20. The required dosages of PEC solution to neutralize the charges of different nanocellulose fractions were determined by ζ-potential measurements, and the CMNF retentions on recycled unbleached fibers were evaluated in a Britt Dynamic Drainage Jar. The results showed that the maximum retention was obtained when the neutral PEC-CMNF system was added to pulp. Besides, a significant decrease on °SR was observed when PEC and PEC-CMNF systems were added to the untreated pulp, limiting the negative effects of nanocellulose addition on pulp drainability. The incorporation of PEC-CMNF systems to the handsheets increased the tensile index (up to 28%), Mullen index (up to 40%) and internal bonding (up to 255%). Finally, the compressive strength of the handsheets, namely SCT and CMT, increased up to 30 and 70%, respectively. These simultaneous improvement on drainability and mechanical properties makes the proposed PEC-CMNF system a promising solution for the production of packaging paper.
... However, there is a global need for rapid and robust CNM size characterisation (Balea et al. 2020). The lack of systematic, streamlined, and reliable methods to characterise CNM sizes at industrial-scale has hindered our ability to control their large-scale production and ensure consistent quality (Kaushik et al. 2015). Of particular interest is the CNM aspect ratio (fibre length divided by fibre width), which strongly influences sheet formation and resulting properties of fibrous materials (Varanasi et al. 2013). ...
Cellulose nanomaterial (CNM) aspect ratio strongly influences sheet formation and resulting mechanical, optical, and barrier properties. However, there is a lack of fast and reliable methods for CNM aspect ratio determination, limiting the reliable production of nanocellulose at industrial-scale. Current laboratory approaches comprise microscopic (e.g. atomic force microscopy (AFM) and transmission electron microscopy (TEM)), and sedimentation methods, which are time-consuming and limited to specific CNM fibre sizes. Here, we describe a new rheological method to determine the aspect ratios for the whole size range of cellulose fibres using rheology. Cellulose nanocrystals (CNCs), cellulose nanofibres (CNFs), and wood fibres in the form of Bleached Eucalyptus Kraft (BEK) were investigated. The aspect ratios of these three scales of cellulose fibres were determined by measuring the specific viscosity profiles of their suspensions at different concentrations from high to low shear rates (2000–0.001 s⁻¹), and evaluating whether the fibre suspensions exhibited entangled or disentangled behaviour. The rheological results agreed well with those produced by AFM and sedimentation methods. Furthermore, cellulose fibre aspect ratios determined with specific viscosity measurements were generated in 5 hours for each feedstock, while sedimentation and AFM required at least 2 days to produce the same results. Ultimately, we demonstrate that rheology is a rapid and accurate method to determine the aspect ratio for the whole range of cellulose fibre sizes, a critical step towards facilitating their full-scale application.
... Electron microscopy is a technique with a nanometer scale resolution and is capable of imaging NBCs including Transmission Electron Microscope(TEM), Scanning Electron Microscope(SEM), and Atomic Force Microscopy (AFM). Electron microscopy enables the direct observation of the dimensions (i.e., length and width) of a given particle [71]. ...
... However, as TEM images are projections of the objects along the incident beam direction, it may be difficult to accurately measure the particle thickness. Depending on the amount of energy that was absorbed by the sample, the intensity of the beam that hits the viewing screen varies, and an image is made [71,72]. [40]. ...
... In order to get an accurate measurement using TEM, the sample should be extremely thin (thickness below well below 1 μm) and well dispersed (no agglomerate) to allow transmission of electrons; additionally, the atomic number, density of the observed material, and on the energy of the incident electrons should be considered. Usually, this can be achieved using sectioning techniques for solid samples or preparation of NBCs using dilute suspensions (dispersion) [71]. Then, the sample is deposited on thin circular metallic grids (copper, carbon, etc.) with typical meshes around a few 10 of micrometers and accurately mounted in the sample holder for microscopy. ...
Nanobiocomposites (NBCs) have many applications in drug delivery, tissue engineering, etc. The need for NBC physicochemical characterization is mandatory before investigating their usefulness in developing drug delivery systems. This chapter will explore the basic and the most recent techniques used in the physicochemical characterization of these biocomposites. Examples of physical properties include morphological properties using microscopy (size, porosity, etc.), particle size analysis and surface charge, powder X-ray diffraction, thermal, mechanical, and rheological properties, etc. Examples of chemical properties include molecular weight determination, solubility and purity assessment, degree of functionalization, and gelling properties, using spectroscopic techniques (UV, MS, NMR, etc.). For each property, the following points will be elucidated: sample preparation, factors affecting the accuracy of the test results, examples of data interpretation from the recently published literature, and test limitations, if any.
... 67−69 Cellulose is ubiquitous with almost endless supply in nature (that is, sustainable), and naturally consists of complex and insoluble substructural fibrous systems. 70 The molecular surface of cellulose is loaded with reactive hydroxyl groups (−OH); at the nanoscale, the reactivities are more pronounced due to enhanced specific surface area and atomic exposures, conferring on nanocellulose high hydrophilicity (good wettability), enhanced functionalization, with notable redox centers (for conduction and the hoping of electrons), while enhancing chain aggregation and possibly cross-linking through intra-and inter-molecular hydrogen bonds which influences densification, chain packing, and barrier properties. 53,71 In addition, the pore configuration, an essential feature of the fibril morphology of nanocellulosics, contributes to the chemical reactivity and enzymatic degradation efficacy; hence, the capacity to efficiently manipulate pore structures in cellulosic materials affords the possibilities for expansive product development that meet various specifications and application needs. ...
Envisage a world where discarded electrical/electronic devices and single-use consumables can dematerialize and lapse into the environment after the end-of-useful life without constituting health and environmental burdens. As available resources are consumed and human activities build up wastes, there is an urgency for the consolidation of efforts and strategies in meeting current materials needs while assuaging the concomitant negative impacts of conventional materials exploration, usage, and disposal. Hence, the emerging field of transient technology (Green Technology), rooted in eco-design and closing the material loop toward a friendlier and sustainable materials system, holds enormous possibilities for assuaging current challenges in materials usage and disposability. The core requirements for transient materials are anchored on meeting multicomponent functionality, low-cost production, simplicity in disposability, flexibility in materials fabrication and design, biodegradability, biocompatibility, and environmental benignity. In this regard, biorenewables such as cellulose-based materials have demonstrated capacity as promising platforms to fabricate scalable, renewable, greener, and efficient materials and devices such as membranes, sensors, display units (for example, OLEDs), and so on. This work critically reviews the recent progress of nanocellulosic materials in transient technologies toward mitigating current environmental challenges resulting from traditional material exploration, usage, and disposal. While spotlighting important fundamental properties and functions in the material selection toward practicability and identifying current difficulties, we propose crucial research directions in advancing transient technology and cellulose-based materials in closing the loop for conventional materials and sustainability.
