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This review emphasizes the practical importance of laser light scattering methods for characterizing cellulose and its derivatives. The physicochemical parameters like molecular weights, the radius of gyration, hydrodynamic radius, and conformation will be considered when the reproducibility of polymer behavior in solution is necessary for the subsequent optimization of the property profile of a designed product. Since there are various sources of cellulose, and the methods of cellulose extraction and chemical modification have variable yields, materials with variable molecular weights, and size polydispersity will often result. Later, the molecular masses will influence other physicochemical properties of cellulosic materials, both in solution and solid state. Consequently, the most rigorous determination of these quantities is imperative. In this regard, the following are presented and discussed in this review: the theoretical foundations of the light scattering phenomenon, the evolution of the specific instrumentation and detectors, the development of the detector-coupling techniques which include a light scattering detector, and finally, the importance of the specific parameters of polymers in solution, resulting from the data analysis of light scattering signals. All these aspects are summarized according to the chemical classification of the materials: celluloses, esters of cellulose, co-esters of cellulose, alkyl esters of cellulose, ethers of cellulose, and other heterogeneous cellulose derivatives with applications in life sciences.

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Natural earthworm with the ability to loosen soils that favors sustainable agriculture has inspired worldwide interest in the design of intelligent actuators. Given the inability to carry heavy loads and uncontrolled deformation, the vast majority of actuators can only perform simple tasks by bending, contraction, or elongation. Herein, a degradable actuator with the ability to deform in desired ways is presented, which successfully mimics the burrowing activities of earthworms to loosen soils with increased soil porosity by digging, grabbing, and lifting the soil when it receives rains. Such a scarifying actuator is made of degradable cellulose acetate and uncrosslinked polyacrylamide via the swelling-photopolymerizing method. The water absorption of polyacrylamide in moisture conditions causes rapid and remarkable bending. Such mechanical bending can be controlled in specific areas of the cellulose acetate film if polyacrylamide is polymerized in a patterned way, so as to generate complicated deformations of the whole cellulose acetate. Patterning polyacrylamide within cellulose acetate is achieved based on reversible surface protection by means of pen writing, rather than the traditional masking techniques. The water-induced deformation of programmable cellulose-based actuators is well preserved in soil, which is appropriate for promoting rain diffusion as well as root breath.

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Solid state nuclear magnetic resonance (ssNMR) is a powerful and attractive characterization method for obtaining insights into the chemical structure and dynamics of a wide range of materials. Current interest in cellulose-based materials, as sustainable and renewable natural polymer products, requires deep investigation and analysis of the chemical structure, molecular packing, end chain motion, functional modification, and solvent-matrix interactions, which strongly dictate the final product properties and tailor their end applications. In comparison to other spectroscopic techniques, on an atomic level, ssNMR is considered more advanced, especially in the structural analysis of cellulose-based materials; however, due to a dearth in the availability of a broad range of pulse sequences, and time consuming experiments, its capabilities are underestimated. This critical review article presents the comprehensive and up-to-date work done using ssNMR, including the most advanced NMR strategies used to overcome and resolve the structural difficulties present in different types of cellulose-based materials.

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To date, flexible pressure sensors built on silver nanowires (AgNWs) have attracted tremendous attention, owing to their versatile applications in wearable, human-interactive, health-monitoring devices. Cellulose and its derivatives, which show great promise in serving flexible pressure sensors as the desired substrate due to their natural abundance, biocompatibility, easy processibility, and low costs. Herein, we reported a rational strategy to design a silver nanowires-dual-cellulose conductive paper. Its morphology, chemical and crystal structures, thermal stability, mechanical performances, and electrical properties were carefully studied. The results suggested that good tensile properties (tensile strength ≤8.10 MPa), high electrical conductivity (≤ 1.74 × 104 S·m-1) with long-term stability, and good adhesion stability (bending cycles over 500) were obtained. Furthermore, the use of such conductive paper as substrate for versatile flexible pressure sensors was demonstrated, which exhibited fast response (~ 0.48 s) and high sensitivity, in response to finger motion, voice recognition, and human pulse, etc.

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BACKGROUND: Cellulose, having huge reserves of natural polymers, has been widely applied in pharmaceutical and biomedicine fields due to its good biocompatibility, biodegradability, non-toxicity and excellent mechanical properties. At present, water- resistant metal-based and petroleum-based materials applied in the medical field have obvious problems of poor biocompatibility and high cost. Therefore, water-resistant cellulose- based materials with good biocompatibility and low price have become an attractive alternative. This review aims to summarize the preparation of water-resistant cellulose- based materials and their potential application in pharmaceutical and biomedical in recent years. METHODS: Common hydrophobic treatments of cellulose fibers or paper were overviewed. The preparation, properties and applications of water-resistant cellulose- based materials in the pharmaceutical and biomedical fields were summarized. RESULTS: Common hydrophobic treatments of cellulose fibers or paper were divided into chemical modification (graft polymerization, crosslinking, solution casting or dip-coating), physico-chemical surface modifications (plasma treatments, surface patterning, electrostatic spraying and electrowetting) and physical processing (electrostatic spinning, SAS process and 3D EHD printing). These hydrophobically processed cellulose fibers or paper could be prepared into various water-resistant cellulose-based materials and applied in pharmaceutical excipients, drug-loaded amphiphilic micelles, drug-loaded composite fibers, hydrophobic biocomposite film/coatings and paper-based detectors. They presented excellent water resistance and biocompatibility, low cytotoxicity and high drug loading ability, and stable drug release rate, etc., which could be used for water-insoluble drugs carriers, wound dressings, and medical testing equipment. CONCLUSION: Currently, water-resistant cellulose-based materials were mainly applied in water-insoluble drugs delivery carriers, wound dressing and medical diagnosis and presented great application prospects. However, the contradiction between hydrophobicity and mechanical properties of these reported water-resistant cellulose-based materials limited their wider application in biomedicine such as tissue engineering. In the future, attention will be focused on the higher hydrophobicity of water-resistant cellulose-based materials with excellent mechanical properties. In addition, clinical medical research of water-resistant cellulose-based materials should be strengthened.

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Online purchasing, and hence e-commerce packaging production and use, have grown steadily in recent years, and so has their environmental impact as a result. This paper reviews the evolution of packaging over the last century through a compilation of scientific literature on e-commerce packaging focusing on its environmental side. The primary aims were to identify research gaps in e-commerce packaging and to propose new research lines aimed at reducing its environmental impact. A systematic search of abstracts was conducted to identify articles dealing with sustainability in e-commerce packaging in order to better understand changes in materials and formats, identify problems such as oversizing and allow prospective readers to become acquainted with the latest innovations in materials, sustainability and logistics. Based on existing research, packaging materials and technology evolved rapidly until the 1990s. Later, however, it has become increasingly difficult to further reduce their cost and environmental impact. Also, some packaging products continue to be made from non-renewable materials and thus restrict growth of e-commerce. Further research is needed with a view to producing new packages from renewable sources such as cellulose-containing materials, which are widely available in nature, or from recycled cellulose-based materials such as cartonboard. Improving distribution processes with new, more effective tools could additionally help alleviate the environmental impact of packaging. Similarly, new production processes such as additive manufacturing and 3D printing might help optimize package volume and shape, thereby facilitating more sustainable production through, for example, reduced CO2 emissions. Currently available technology can be useful to rethink the whole e-commerce packaging paradigm, which has changed very little over the past few decades.

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A novel hydrophobic cellulose-based organic/inorganic nanomaterial (cellulose/TS-POSS) was prepared by oxygen plasma treatment followed by condensation reaction with TriSilanollsobutyl-Polyhedral oligomeric silsesquioxane. By careful design of cellulose film modified with TS-POSS by plasma etching, not only simply activated the hydroxyl groups on fiber surface, but also lowered the surface energy and increased the surface roughness. The surface morphology, chemical structure, thermal properties, and hydrophobic properties of cellulose/TS-POSS materials were systematically investigated by FTIR, SEM, AFM, CA, and TGA, respectively. The experimental results showed that the static water contact angle of cellulose/TS-POSS was 152.9°, demonstrating super-hydrophobicity. The results indicated that the TS-POSS were observed uniformly dispersed in the cellulose at the nanometer scale to form nanostructures, successful bonding to cellulose through condensation reaction. This process developed in this paper provided new solutions and approximations for the facile fabrication of sustainable cellulose-based hydrophobic materials.

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Nature has been producing cellulose since long before man walked the surface of the earth. Millions of years of natural design and testing have resulted in cellulose-based structures that are an inspiration for the production of synthetic materials based on cellulose with properties that can mimic natural designs, functions, and properties. Here, five sections describe cellulose-based materials with characteristics that are inspired by gratings that exist on the petals of the plants, structurally colored materials, helical filaments produced by plants, water-responsive materials in plants, and environmental stimuli-responsive tissues found in insects and plants. The synthetic cellulose-based materials described herein are in the form of fibers and films. Fascinating multifunctional materials are prepared from cellulose-based liquid crystals and from composite cellulosic materials that combine functionality with structural performance. Future and recent applications are outlined.

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Multifuntional fabrics with special wettability have attracted a lot of interest in both fundamental research and industry applications over the last two decades. In this review, recent progress of various kinds of approaches and strategies to construct super-antiwetting coating on cellulose-based substrates (fabrics and paper) has been discussed in detail. We focus on the significant applications related to artificial superhydrophobic fabrics with special wettability and controllable adhesion, e.g., oil-water separation, self-cleaning, asymmetric/anisotropic wetting for microfluidic manipulation, air/liquid directional gating, and micro-template for patterning. In addition to the anti-wetting properties and promising applications, particular attention is paid to coating durability and other incorporated functionalities, e.g., air permeability, UV-shielding, photocatalytic self-cleaning, self-healing and patterned antiwetting properties. Finally, the existing difficulties and future prospects of this traditional and developing field are briefly proposed and discussed.