A Bottom-Up Synthesis of Vinyl-Cellulose Nanosheets and Their Nanocomposite Hydrogels with Enhanced Strength

Extracted nanocellulose from natural resources commonly requires modification before it is used as an effective nanofiller. In the present study, through an enzymatic polymerization of α-d-glucose 1-phosphate from the primer 2-(glucosyloxy)­ethyl methacrylate (GEMA), a novel type of two-dimensional methacrylate-containing cellulose nanosheets (CNS) with a thickness of about 6 nm, named as GEMA-CNS, was directly synthesized under a mild condition by a “bottom-up” method. The structure and morphology of GEMA-CNS were characterized by ¹H-nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time-of-flight mass spectra (MALDI-TOF MS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Afterward, the obtained GEMA-CNS was covalently incorporated into poly­(ethylene glycol) matrix through thiol–ene Michael addition, fabricating a series of GEMA-CNS-based nanocomposite hydrogels. The addition of GEMA-CNS effectively improved the mechanical strength and altered the internal network structures of hydrogels; additionally, the swelling/biodegradation behaviors of gels in phosphate buffer saline (pH 7.4) at 37 °C were affected to some degree. This species of property-tunable hydrogels with GEMA-CNS dosage demonstrates potential applications in tissue engineering. The current presentation opens a new road for direct enzymatic preparation of reactive nanocellulose and its novel applications in nanocomposite materials

CQDs-Doped Magnetic Electrospun Nanofibers: Fluorescence Self-Display and Adsorption Removal of Mercury(II)

This paper reports the carbon quantum dots-doped magnetic electrospinning nanofibers for the self-display and removal of Hg­(II) ions from water. The fluorescent carbon quantum dots and magnetic Fe₃O₄ nanoparticles were pre-prepared successfully, and they appeared to be homogeneously dispersed in nanofibers via electrospinning. During the sorption of Hg­(II) ions, the significant fluorescence signals of nanofibers gradually declined and exhibited a good linear relationship with cumulative adsorption capacity, which could be easily recorded by the photoluminescence spectra. The sorption performance of mercury ions onto the nanofibers was investigated in terms of different experimental factors including contact time, solution pH value, and initial ion concentration. Considering the actual parameters, the nanofibers were sensitive self-display adsorption system for Hg­(II) ions in the existence of other cation. The sorption data were described by different kinetic models, which indicate that the whole sorption was controlled by chemical adsorption. The intraparticle diffusion mass transfer was not obvious in this system, which further proved the uniform adsorption and even fluorescence quenching in nanofibers. Additionally, the nanocomposite fiber could regenerate in several cycles with no significant loss of adsorption capacity and fluorescence intensity. Thus, the nanofibers are promising alternatives for environmental pollution incidents. It is especially competent due to its high efficiency for self-display and removal of high concentration of mercury ions

Cellulosic Biomass-Reinforced Polyvinylidene Fluoride Separators with Enhanced Dielectric Properties and Thermal Tolerance

Safety issues are critical barriers to large-scale energy storage applications of lithium-ion batteries (LIBs). Using an ameliorated, thermally stable, shutdown separator is an effective method to overcome the safety issues. Herein, we demonstrate a novel, cellulosic biomass-material-blended polyvinylidene fluoride separator that was prepared using a simple nonsolvent-induced phase separation technique. This process formed a microporous composite separator with reduced crystallinity, uniform pore size distribution, superior thermal tolerance, and enhanced electrolyte wettability and dielectric and mechanical properties. In addition, the separator has a superior capacity retention and a better rate capability compared to the commercialized microporous polypropylene membrane. This fascinating membrane was fabricated via a relatively eco-friendly and cost-effective method and is an alternative, promising separator for high-power LIBs

Thermally Stable Cellulose Nanocrystals toward High-Performance 2D and 3D Nanostructures

Cellulose nanomaterials have attracted much attention in a broad range of fields such as flexible electronics, tissue engineering, and 3D printing for their excellent mechanical strength and intriguing optical properties. Economic, sustainable, and eco-friendly production of cellulose nanomaterials with high thermal stability, however, remains a tremendous challenge. Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through fully recyclable oxalic acid (OA) hydrolysis along with disk-milling (DM) pretreatment of bleached kraft eucalyptus pulp. Compared with the commonly used cellulose nanocrystals from sulfuric acid hydrolysis, DM-OA-CNCs show several advantages including large aspect ratio, carboxylated surface, and excellent thermal stability along with high yield. We also successfully demonstrate the fabrication of high-performance films and 3D-printed patterns using DM-OA-CNCs. The high-performance films with high transparency, ultralow haze, and excellent thermal stability have the great potential for applications in flexible electronic devices. The 3D-printed patterns with porous structures can be potentially applied in the field of tissue engineering as scaffolds