Advanced Characterization of Self-Fibrillating Cellulose Fibers and Their Use in Tunable Filters

Abstract

Thorough characterization and fundamental understanding of cellulose fibers can help us develop new, sustainable material streams and advanced functional materials. As an emerging nanomaterial, cellulose nanofibrils (CNFs) have high specific surface area and good mechanical properties; however, handling and processing challenges have limited their widespread use. This work reports an in-depth characterization of self-fibrillating cellulose fibers (SFFs) and their use in smart, responsive filters capable of regulating flow and retaining nanoscale particles. By combining direct and indirect characterization methods with polyelectrolyte swelling theories, it was shown that introduction of charges and decreased supramolecular order in the fiber wall were responsible for the exceptional swelling and nanofibrillation of SFFs. Different microscopy techniques were used to visualize the swelling of SFFs before, during, and after nanofibrillation. Through filtration and pH adjustment, smart filters prepared via in situ nanofibrillation showed an ability to regulate the flow rate through the filter and a capacity of retaining 95% of 300 nm (diameter) silica nanoparticles. This exceptionally rapid and efficient approach for making smart filters directly addresses the challenges associated with dewatering of CNFs and bridges the gap between science and technology, making the widespread use of CNFs in high-performance materials a not-so-distant reality.

Toward Li-ion Graphite Anodes with Enhanced Mechanical and Electrochemical Properties Using Binders from Chemically Modified Cellulose Fibers

“…In addition to their carboxyl groups, TPCs also exhibit reactive aldehydes that are introduced by opening the AGU at the C2–C3 positions, which grant them further chemical functionalities. Most notably, they possess the ability to form hemiacetal cross-links when brought in close proximity to hydroxyl groups that are readily available on cellulose surfaces, making TPC a versatile option for various applications . This cross-linking approach has, for example, recently been used in the preparation of wet-stable cellulosic materials, making it particularly interesting for designing strong electrodes.…”

“…Most notably, they possess the ability to form hemiacetal crosslinks when brought in close proximity to hydroxyl groups that are readily available on cellulose surfaces, making TPC a versatile option for various applications. 28 This cross-linking approach has, for example, recently been used in the preparation of wet-stable cellulosic materials, 29 making it particularly interesting for designing strong electrodes. Aldehydes are also known for their favorable interactions with graphitic surfaces, which could help further strengthen the composite structure of the anodes.…”

Cellulose-reinforced poly(ethylene-co-vinyl acetate)-supported Ag nanoparticles with excellent catalytic properties: synthesis of thioamides using the Willgerodt–Kindler reaction

“…27,28 Cellulose is primarily found in plants and also in some animals and bacteria. 29,30 Because of the spherical and porous beads of cellulose, its catalytic efficacy can be significantly increased via the insertion of metal ions and NPs into its matrix. 31 Moreover, chemically modified hydrophobic cellulose has been increasingly used.…”

Rapidly Prepared Nanocellulose Hybrids as Gas Barrier, Flame Retardant, and Energy Storage Materials

“…CNFs have previously been used in combination with other components such as clays or carbons to prepare hybrids with different functionalities such as gas barrier, , flame retardancy, , and energy storage. , Despite their exciting properties, there are unresolved challenges in transitioning these hybrid materials from research to commercial adoption. These challenges are mainly related to CNFs’ time-consuming and energy-intensive production and processing into dry materials (i.e., costly CNF extraction and slow water removal). − We have recently demonstrated a two-step oxidation of cellulose fibers in aqueous media that can yield self-fibrillating fibers (SFFs). , Using SFFs, CNFs can be liberated and processed into nanopapers simultaneously via an increase in pH (≥pH 10). These SFF-based CNFs are pH-responsive and self-associative in a reversible manner due to their surface carboxyl and aldehyde groups.…”

“…16−18 We have recently demonstrated a two-step oxidation of cellulose fibers in aqueous media that can yield self-fibrillating fibers (SFFs). 19,20 Using SFFs, CNFs can be liberated and processed into nanopapers simultaneously via an increase in pH (≥pH 10). These SFF-based CNFs are pHresponsive and self-associative in a reversible manner due to their surface carboxyl and aldehyde groups.…”