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

• Published in: ACS applied materials & interfaces Vol. 13; no. 27; pp. 32467 - 32478
• Main Authors: Gorur, Yunus Can, Reid, Michael S, Montanari, Céline, Larsson, Per Tomas, Larsson, Per A, Wågberg, Lars
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.07.2021
• Subjects: Cellulose; cellulose fibers; Cellulose nanocrystals; Cellulose nanofibrils (CNFs); Characterization methods; CNF; filter paper; Filtration; Functional materials; green materials; High performance material; High specific surface area; Microscopy technique; nanofibrillation; Nanoparticles; Natural fibers; Polyelectrolytes; Science and Technology; Silica; Silica nanoparticles; Supramolecular ordering; Surfaces, Interfaces, and Applications; Sustainable materials; Swelling; Textile fibers; green materials; cellulose fibers; CNF; nanofibrillation; filter paper
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.1c06452

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.