In the history of cellulose chemistry, hydrogen bonding has been the predominant explanation when discussing intermolecular interactions between cellulose polymers. This is the general consensus in ...scholarly textbooks and in many research articles, and it applies to several other biomacromolecules' interactions as well. This rather unbalanced description of cellulose has likely impacted the development of materials based on the processing of cellulose-for example, via dissolution in various solvent systems and regeneration into solid materials, such as films and fibers, and even traditional wood fiber handling and papermaking. In this review, we take as a starting point the questioning of the general description of the nature of cellulose and cellulose interactions initiated by Professor Björn Lindman, based on generic physicochemical reasoning about surfactants and polymers. This dispute, which became known as "the Lindman hypothesis", highlights the importance of hydrophobic interactions in cellulose systems and that cellulose is an amphiphilic polymer. This paper elaborates on Björn Lindman's contribution to the subject, which has caused the scientific community to revisit cellulose and reconsider certain phenomena from other perspectives.
Polymeric multilayer capsules formed by the Layer-by-Layer (LbL) technique are interesting candidates for the purposes of storage, encapsulation, and release of drugs and biomolecules for ...pharmaceutical and biomedical applications. In the current study, cellulose-based core-shell particles were developed via the LbL technique alternating two cellulose derivatives, anionic carboxymethylcellulose (CMC), and cationic quaternized hydroxyethylcellulose ethoxylate (QHECE), onto a cationic vesicular template made of didodecyldimethylammonium bromide (DDAB). The obtained capsules were characterized by dynamic light scattering (DLS), ζ potential measurements, and high-resolution scanning electron microscopy (HR-SEM). DLS measurements reveal that the size of the particles can be tuned from a hundred nanometers with a low polydispersity index (deposition of 2 layers) up to micrometer scale (deposition of 6 layers). Upon the deposition of each cellulose derivative, the particle charge is reversed, and pH is observed to considerably affect the process thus demonstrating the electrostatic driving force for LbL deposition. The HR-SEM characterization suggests that the shape of the core-shell particles formed is reminiscent of the spherical vesicle template. The development of biobased nano- and micro-containers by the alternating deposition of oppositely charged cellulose derivatives onto a vesicle template offers several advantages, such as simplicity, reproducibility, biocompatibility, low-cost, mild reaction conditions, and high controllability over particle size and composition of the shell.
Cellulose acetate butyrate (CAB) is a possible candidate, being a raw material derived from renewable resources, to replace fossil-based materials. This is due to its thermoplastic properties and the ...relative ease with which it could be implemented within the existing industry. With a significant amount of variation in CAB on the market today, a knowledge gap has been identified regarding the understanding of the polymer structural arrangement in films. This relates to the underlying mechanisms that regulate CAB film material properties, insights that are important in product development. In this study, commercially available CAB was investigated with XRD, SEM, AFM, and TOPEM DSC in order to obtain physicochemical information related to its micro-structural features in solvent-cast films. The film-forming ability relates mostly to the number of hydroxyl groups, and the semi-crystallinity of the films depends on the type and position of the side groups along the cellulose backbone. The appearance of signs of possible cholesteric ordering in the films could be connected to higher amounts of hydroxyl groups along the backbone that disturb the helix arrangement, while the overall order was primarily related to the butyrate substitution and secondarily related to the molecular weight of the particular CAB studied. Cold crystallization was also observed in one CAB sample.
Proteomic analysis offers a new approach to identify a broad spectrum of genes that are expressed in living systems. We applied a proteomic approach to study changes in wheat grain in response to ...drought, a major environmental parameter adversely affecting development and crop yield. Three wheat genotypes differing in genetic background were cultivated in field under well-watered and drought conditions by following a randomized complete block design with four replications. The overall effect of drought was highly significant as determined by grain yield and total dry matter. About 650 spots were reproducibly detected and analyzed on 2-DE gels. Of these, 121 proteins showed significant change under drought condition in at least one of the genotypes. Mass spectrometry analysis using MALDI-TOF/TOF led to the identification of 57 proteins. Two-thirds of identified proteins were thioredoxin (Trx) targets, in accordance with the link between drought and oxidative stress. Further, because of contrasting changes in the tolerant and susceptible genotypes studied, several proteins emerge as key participants in the drought response. In addition to providing new information on the response to water deprivation, the present study offers opportunities to pursue the breeding of wheat with enhanced drought tolerance using identified candidate genetic markers. The 2-DE database of wheat seed proteins is available for public access at http://www.proteome.ir.
Chelating surfactants are amphiphilic molecules capable of forming coordination complexes with metal ions and self-assembling into organized structures. These compounds have gained significant ...attention in recent years due to their multifaceted applications in environmental remediation, industrial processes, and material sciences. This review provides an overview of the characterization techniques and recent advancements in the applications of chelating surfactants over the past few years. The review begins by elucidating the characterization methods employed to understand the physicochemical properties of chelating surfactants and gain insight into their complex behavior and interactions in various systems. The applications of chelating surfactants in remediation of wastewater and soil, flotation of minerals, oil recovery processes, and corrosion inhibition in metallic structures are explored. Through examination of recent fundamental research activities, innovative approaches, mechanisms of action, and advancements in the different application domains are highlighted. Lastly, some recent progress in the related field of metallosurfactants is explored, even though not all metallosurfactants are chelating.
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•A combination of neutron reflection and surface tension measurements provide insights into the interaction of molecules in a surface layer. The study discusses the direct observation of the composition, which allows models based on thermodynamic theories to be examined.•A comprehensive compilation of earlier research on chelating surfactants can be found in this review.•This study reveals the complex self-assembly and intermolecular interactions among chelating surfactants and highlights important characterization techniques.•The study shows how electrokinetic remediation can further improve chelating surfactants' remediation capacity.•The selective flotation performance for separating valuable minerals from gauge materials using chelating surfactants is demonstrated. Furthermore, important characterization techniques to elucidate the mechanism of action are revealed.•The study highlights the advantages of utilizing the pH-responsiveness of chelating surfactants for stepwise separation of valuable minerals by tuning the pH.•The authors have demonstrated the possibilities for using amino acid-based chelating surfactants in enhanced oil recovery and explained their wettability modification in various reservoir conditions.•The application of amino acid-based chelating surfactants as corrosion inhibitors is demonstrated, and their adsorption mechanisms are discussed.•A comprehensive review focusing on metallosurfactant aggregate interactions with biomolecules, synthesis of nanoparticles, and an extensive part on biomedical applications.•Here is a comprehensive study of biomolecular interactions with metallosurfactants showing an effective binding affinity with DNA.
Aqueous sodium hydroxide solutions are extensively used as solvents for lignin in kraft pulping. These are also appealing systems for cellulose dissolution due to their inexpensiveness, ease to ...recycle and low toxicity. Cellulose dissolution occurs in a narrow concentration region and at low temperatures. Dissolution is often incomplete but additives, such as zinc oxide or urea, have been found to significantly improve cellulose dissolution. In this work, lignin was explored as a possible beneficial additive for cellulose dissolution. Lignin was found to improve cellulose dissolution in cold alkali, extending the NaOH concentration range to lower values. The regenerated cellulose material from the NaOH-lignin solvents was found to have a lower crystallinity and crystallite size than the samples prepared in the neat NaOH and NaOH-urea solvents. Beneficial lignin-cellulose interactions in solution state appear to be preserved under coagulation and regeneration, reducing the tendency of crystallization of cellulose.
•Evaluation of lignin as a potential renewable and green additive for cellulose dissolution.•Lignin improves cellulose dissolution in cold alkali, extending the NaOH concentration window.•Gelation kinetics (with aging or temperature) delayed by the addition of lignin.•At low alkali conditions, lignin is more efficient than urea in promoting dissolution.•Lignin induces lower crystallinity in the regenerated cellulose materials.
Inks and toners used for printing contain materials, such as polyester, with strong triboelectric properties to enhance the binding effects, making wastepaper, such as magazines and newspapers, good ...candidates for triboelectric materials. Herein, high‐output power triboelectric nanogenerators (TENGs) that utilize wastepaper as triboelectric layers (wastepaper‐based triboelectric nanogenerators (WP–TENGs)) are reported. Journal paper and office copy paper wastes are investigated. The results show that the maximum power densities of the WP–TENGs reach 43.5 W m−2, which is approximately 250 times the previously reported output of the TENG with a recycled triboelectric layer made from wastepaper. The maximum open circuit voltage (V
OC) and short circuit current (I
SC) are 774 V and 3.92 mA (784 mA m−2), respectively. These findings can be applied to extend the life cycle of printed papers for energy harvesting, and they can later be applied for materials recycling to enhance the sustainable development of our society.
Triboelectric nanogenerators with output power densities reaching 43.5 W m−2 have been made with wastepaper from printed copy paper and journal paper. The high triboelectric effect of the wastepaper occurs due to the additives in the toner/ink for printing. The findings can extend the life cycle of paper products, contributing to sustainable development.
Cellulose has shown great potential in the development of green triboelectric nanogenerators. Particularly, regenerated cellulose (R-cellulose) has shown remarkably high output power density but the ...structural features and key parameters that explain such superior performance remain unexplored. In this work, wood cellulose fibers were dissolved in a LiOH(aq)-based solvent to produce a series of R-cellulose films. Regeneration in different alcohols (from methanol to n-pentanol) was performed and the films’ structural features and triboelectric performance were assessed. Nonsolvents of increased hydrophobicity led to R-cellulose films with a more pronounced (1–10) diffraction peak. An open-circuit voltage (V
OC
) of up to ca. 260 V and a short-circuit current (I
SC
) of up to ca. 150 µA were measured for R-cellulose against polytetrafluoroethylene (as negative counter-layer). However, R-cellulose showed an increased V
OC
of 175% (from 88.1 V) against polydimethylsiloxane when increasing the alcohol hydrocarbon chain length from methanol to n-pentanol. The corresponding I
SC
and output power also increased by 76% (from 89.9 µA) and by 382% (from 8.8 W m
–2
), respectively. The higher R-cellulose hydrophilicity, combined with soft counter-tribolayer that follow the surface structures increasing the effective contact area, are the leading reasons for a superior triboelectric performance.
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Cellulose laminates represent a remarkable convergence of natural materials and modern engineering, offering a wide range of versatile applications in sustainable packaging, construction, and ...advanced materials. In this study, novel all-cellulose laminates are developed using an environmentally friendly approach, where freshly regenerated cellulose II films are stacked without the need for solvents (for impregnation and/or partial dissolution), chemical modifications, or resins. The structural and mechanical properties of these all-cellulose laminates were thoroughly investigated. This simple and scalable procedure results in transparent laminates with exceptional mechanical properties comparable to or even superior to common plastics, with E-modulus higher than 9 GPa for a single layer and 7 GPa for the laminates. These laminates are malleable and can be easily patterned. Depending on the number of layers, they can be thin and flexible (with just one layer) or thick and rigid (with three layers). Laminates were also doped with 10 wt% undissolved fibers without compromising their characteristics. These innovative all-cellulose laminates present a robust, eco-friendly alternative to traditional synthetic materials, thus bridging the gap between environmental responsibility and high-performance functionality.
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