Figure 1 (a-c) were incorrectly assigned in the caption. The correct legend should read: "a-c) Photographs of the cellulose hydrogels: (a) physically cross-linked cellulose hydrogel, (b) DC cellulose hydrogel, and (c) chemically cross-linked cellulose hydrogel under bending." A reflection peak was incorrectly assigned throughout the manuscript. All occurrences of (200) should be changed to (110). All reflections labeled initially (110) in the manuscript instead represent (110) In consequence two passages on page 6282 should read as follows: "…which correspond to the (110) and (110) reflections, respectively, of cellulose II crystallite. [26] Therefore, …resulted from the (110) reflection of the cellulose II crystallite hydrates…". and "…the intensity of the peak at 20.2° for the (110) reflection of the cellulose II crystallite hydrates gradually increased, …" in addition text on page 6283 should appear as "Moreover, the intensity of the (110) reflection of the DC cellulose hydrogels increased as the concentration of aqueous ethanol increased…" and the corrected version of Figure 3 should appear as shown below: correction Figure 3. X-ray diffraction profi les of the PC cellulose hydrogel, DC cellulose hydrogel, and CC cellulose hydrogel prepared using a) different ECH-to-AGU molar ratios and b) different concentrations of aqueous ethanol. The above errors do not affect the scientific conclusions drawn from the work. The authors apologize for any inconvenience or misunderstanding that these errors may have caused.
Crystalline polysaccharides are useful for important and rapidly growing applications ranging from advanced energy storage, green electronics, and catalyst or enzyme supports to tissue engineering and biological devices. However, the potential value of chitin in such applications is currently neglected because of its poor swellability, reactivity, and solubility in most commonly used solvents. Here, a high‐efficiency, energy‐saving, and “green” route for the fabrication of extremely strong and transparent chitin films is described in which chitin is dissolved in an aqueous KOH/urea solution and neutralized in aqueous ethanol solution. The neutralization temperature, ethanol concentration, and chitin solution deacetylation time are critical parameters for the self‐assembly of chitin chains and for tuning the morphology and aggregate structures of the resulting chitin hydrogels and films. Moreover, the drawing orientation can produce extremely strong and tough chitin films with a tensile strength, Young's modulus, and work of fracture of 226 MPa, 7.2 GPa, and 20.3 MJ m−3, respectively. The method developed here should contribute to the utilization of seafood waste and, thereby, to the sustainable use of marine resources.
Robust and flexible cellulose sponges were prepared by dual-cross-linking cellulose nanofiber (CNF) with γ-glycidoxypropyltrimethoxysilane (GPTMS) and polydopamine (PDA) and used as carriers of metal nanoparticles (NPs), such as palladium (Pd). In situ growth of Pd NPs on the surface of CNF was achieved in the presence of polydopamine (PDA). The modified sponges were characterized with FT-IR, XRD, EDX, SEM, TEM, and TGA. XRD, EDX, and TEM results revealed that the Pd NPs were homogeneously dispersed on the surface of CNF with a narrow size distribution. The catalysts could be successfully applied to heterogeneous Suzuki and Heck cross-coupling reactions. Leaching of Pd was negligible and the catalysts could be conveniently separated from the products and reused.
A self‐healing polysaccharide hydrogel based on dynamic covalent enamine bonds has been prepared with a facile, cost‐effective, and eco‐friendly way. The polysaccharide hydrogel is obtained by mixing cellulose acetoacetate (CAA) aqueous solution with chitosan aqueous solution under room temperature. CAA is synthesized by reaction of cellulose with tert‐butyl acetoacetate (t‐BAA) in ionic liquid 1‐allyl‐3‐methylimidazolium chloride (AMIMCl). The structure and properties of CAA are characterized by FT‐IR, NMR, and solubility measurements. The results demonstrate that CAA possesses water solubility with a degree of substitution (DS) about 0.58–1.11. The hydrogel shows an excellent self‐healing behavior without other external stimuli and good stability under physiological conditions. Furthermore, the polysaccharide hydrogel exhibits pH responsive properties.
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