Nanocellulose: A Multipurpose Advanced Functional Material

Nanocellulose refers to the cellulosic material having at last one dimension at nanoscale. It is the most abundant natural polymer on Earth, extracted from plants termed as plant cellulose and produced by microbial cells termed as bacterial cellulose (BC) or bacterial nanocellulose (BNC). Over the past few decades, different forms of nanocellulose have received immense consideration owing due to its abundance, renewability, remarkable structural and physical properties, high surface area and special surface chemistry, high crystallinity and mechanical strength, hydrophilicity, moldability, excellent biological features (biocompatibility, biodegradability, and non-toxicity), and polyfunctionality. These properties are tuned through the addition of other natural and synthetic polymers and nanoparticles via different methods as well as through the incorporation of additional functional groups and by varying the growth and culture conditions of the cellulose-producing microbial cells to produce gels, sheets, films, membrane, pellets, filaments, fibers, papers, tubes, capsules, sponges, laminates, and coatings, which find applications in food, tissue engineering, wound dressing, drug delivery, bioink for 3D printing, biosensors, energy storage devices, membrane filters, textiles, flexible displays, facial masks, and so on. Further, its surface chemistry, porosity, fiber orientation, and physical structure can be controlled at macro-, micro-, and even nanoscales.

The global environmental degradation issue, the depletion of natural energy resources, health-related problems, and other human needs are greatly pushing materials-related research towards the use of various polymeric materials from renewable resources like plants (i.e. cellulose, hemicellulose, lignin) and microorganisms (i.e. BNC) for fabrication of functional materials for different applications. Although nanocellulose obtained from such sources possesses unique features, it lacks antimicrobial activity and magnetic features. Nanocellulose also possesses limited biocompatibility and optical transparency, and requires complex extraction procedures, post-synthesis processing, and complicated functionalization approaches to tune it’s properties to meet the demands of desired application. This can also be costly, time-consuming, and with low yields, thus limiting nanocellulose’s broad-spectrum applications. Even though various studies have been reported on cost-effective synthesis, processing, and structure modification of nanocellulose, there is still much to be explored about its facile and low-cost synthesis, the molecular and chemical regulation of synthesis mechanism, tuning and modification, and novel applications. Taking the advantages of unique surface chemistry and physical structure, this Research Topic is aimed to explore the structural, physico-chemical, mechanical, thermal, and biological features of nanocellulosic materials through the development of their composites with other materials, for their use in the fabrication of advanced functional materials. The aim is to meet the human demand for these advanced functional materials, especially in the biomedical, energy, pharmaceutics, infrastructure, additive manufacturing, paper, textile, environment, and food industries.

The aim of this Research Topic is to cover the promising and recent trends of synthesis and applications of nanocellulose-based materials. Authors are welcome to contribute Original Research articles, Mini- and full-length Reviews, and Communications on the related topics. Areas to be covered in the Research Topic may include, but are not limited to:

• Synthesis and characterization of nanocellulosic materials from renewable resources (production, molecular and metabolic regulation, advancements in characterization)
• Fabrication of nanocellulose-based hydrogels, aerogels, membranes, films, fibers, tubes, capsules, sponges, coatings, laminates, papers, and others with tuned features
• Functionalization: chemical modification and composite synthesis
• Tuning the structural features
• Applications
 Biomedical (Tissue engineering and regenerative medicines, drug delivery, Biosensors, 3D printing)
 Energy (Supercapacitors, solar cells)
 Opto-electroncis (OLEDs, flexible displays)
 Paper industry (specialty paper)
 Food (Packaging, edible)
 Environment (membrane filters, water decontamination, heavy metals removal)
 Textile
 Cosmetics (facial masks)
 Others

Drs. Ullah and Yang hold patents related to cellulose material. All other Topic Editors declare no competing interests with regard to the Research Topic subject.

This Research Topic is dedicated to Prof. Lina Zhang on the occasion of her 80th Birthday, in gratitude, esteem, and affection.