High-Strength Nanostructured Film Based on β-Chitin Nanofibrils from Squid Illex argentinus Pens by 2,2,6,6-Tetramethylpiperidin-1-yl Oxyl-Mediated Reaction

Abstract

2,2,6,6-Tetramethylpiperidin-1-yl oxyl (TEMPO)-oxidized β-chitin nanofibrils (T-ChNF) are novel nanofibrils of high strength and stiffness and can also enhance the adsorption of chitosan in materials for biomedical applications. This study presents the preparation, structure, and properties of T-ChNF based on squid pens. Our nanofibrils have a zeta potential of −25.3 mV at neutral pH and a carboxylic content of 0.17 mmol/g, making hydrocolloid suspension stable at alkaline and neutral pH. It was demonstrated that positively charged chitosan could be adsorbed on the negatively charged surface of T-ChNF, leading to charge neutralization. The key to strong squid pen T-ChNF is the initial raw squid chitin properties and the high degree of acetylation (DA = 99.9%). The T-ChNF diameter is ∼4.4 nm, and the length is in the micrometer range. The length and diameter are similar to those of squid pen β-chitin fibrils prepared under mild conditions. These qualities of fibrils resulted in high-strength (176 MPa) chitin films prepared using the rapid vacuum filtration and drying technique. T-ChNF-based films are ductile, flexible, and transparent.

Single Molecular Layer of Chitin Sub‐Nanometric Nanoribbons: One‐Pot Self‐Exfoliation and Crystalline Assembly into Robust, Sustainable, and Moldable Structural Materials

“…This robust mechanical performance is superior to most of reported chitin films prepared by self‐assembly of nanofibrils or regeneration of chitin solutions (Figure 4I; Table S4, Supporting Information). [ 17c,24 ]…”

Tailor the Deacetylation for High Yield Preparation of Carboxyl β-Chitin Nanofibers from Squid Pen by TEMPO Oxidation

“…2,2,6,6-tetramethylpiperidine-1-oxy-lradical (TEMPO) oxidation is a classical and effective method to obtain carboxyl chitin nanomaterials that can be properly dispersed in alkaline conditions (Lasseuguette et al 2008;Wu et al 2021; Ye et al 2021). For example, in a pioneering work, Fan et al (Fan et al 2008a) successfully prepared anionic chitin nanocrystals (COO − , length 340 nm, width 8 nm) using α-chitin from crab shell by TEMPO/NaBr/NaClO (TBN) oxidation system, the hydroxyl group on C6 of chitin is rstly selectively oxidized to the aldehyde group and nally to the carboxyl group.…”