Water-soluble cellulose ethers are widely used as stabilizers, thickeners, and viscosity modifiers in many industries. Understanding rheological behavior of the polymers is of great significance to the effective control of their applications. In this work, a series of cyanoethylcellulose (CEC) samples with different molecular weights were prepared with cellulose and acrylonitrile in NaOH/urea aqueous solution under the homogeneous reaction. The rheological properties of water-soluble CECs as a function of concentration and molecular weight were investigated using shear viscosity and dynamic rheological measurements. Viscoelastic behaviors have been successfully described by the Carreau model, the Ostwald-de-Waele equation, and the Cox–Merz rule. The entanglement concentrations were determined to be 0.6, 0.85, and 1.5 wt% for CEC-11, CEC-7, and CEC-3, respectively. All of the solutions exhibited viscous behavior rather than a clear sol-gel transition in all tested concentrations. The heterogeneous nature of CEC in an aqueous solution was determined from the Cox–Merz rule due to the coexistence of single chain complexes and aggregates. In addition, the CEC aqueous solutions showed good thermal and time stability, and the transition with temperature was reversible.
Abstract Owing to the high specific surface area and lightweight, aerogels exhibit excellent adsorption capacity that can be tailored for the fabrication of high‐performance environmental purification materials. Cellulose nanocrystal (CNC) is an abundant, bio‐based, low‐density one dimensional (1D) nanomaterials with high‐respect ratio. In this work, CNC is first chemically grafted with polyethylenimine (PEI) and further by β ‐cyclodextrin ( β ‐CD), which is subsequently crosslinked by polyacrylamide (PAM) to prepare the composted aerogel (CNC‐PEI‐CD/PAM), and being endowed high‐adsorption capacity for methyl orange (MO) (155.93 mg g −1 ) and removal rate (97.46%). Our unique strategy overcomes the low graft efficiency of β ‐CD directly onto CNC by connecting PEI. Besides, CNC‐PEI‐CD/PAM not only shows superior adsorption performance to methyl orange, attributing to the unique “selective” cavity structure of β ‐CD and dense surface charge of PEI, but also displays the desired reusability. This material shows the huge potential in water purification.
In order to overcome the pandemic of COVID-19, messenger RNA (mRNA)-based vaccine has been extensively researched as a rapid and versatile strategy. Herein, we described the immunogenicity of mRNA-based vaccines for Beta and the most recent Omicron variants. The homologous mRNA-Beta and mRNA-Omicron and heterologous Ad5-nCoV plus mRNA vaccine exhibited high-level cross-reactive neutralization for Beta, original, Delta, and Omicron variants. It indicated that the COVID-19 mRNA vaccines have great potential in the clinical use against different SARS-CoV-2 variants.
Liquid metal (LM) nanodroplets and MXene nanosheets are integrated with sulfonated bacterial nanocellulose (BNC) and acrylic acid (AA). Upon fast sonication, AA polymerization leads to a crosslinked composite hydrogel in which BNC exfoliates Mxene, forming organized conductive pathways. Soft conducting properties are achieved in the presence of colloidally stable core-shell LM nanodroplets. Due to the unique gelation mechanism and the effect of Mxene, the hydrogels spontaneously undergo surface wrinkling, which improves their electrical sensitivity (GF = 8.09). The hydrogels are further shown to display interfacial adhesion to a variety of surfaces, ultra-elasticity (tailorable elongation, from 1000 % to 3200 %), indentation resistance and self-healing capabilities. Such properties are demonstrated in wearable, force mapping, multi-sensing and patternable electroluminescence devices.
Abstract Lipoic acid (LA), which originates from animals and plants, is a small biomass molecule and has recently shown great application value in soft conductors. However, the severe depolymerization of LA places a significant limitation on its utilization. A strategy of using Li‐bonds as both depolymerization quenchers and dynamic mediators to melt transform LA into high‐performance ionoelastomers (IEs) is proposed. They feature dry networks while simultaneously combining transparency, stretchability, conductivity, self‐healing ability, non‐corrosive property, re‐mouldability, strain‐sensitivity, recyclability, and degradability. Most of the existing soft conductors’ drawbacks, such as the tedious synthesis, non‐renewable polymer networks, limited functions, and single‐use only, are successfully solved. In addition, the multi‐functions allow IEs to be used as soft sensors in human–computer interactive games and wireless remote sports assistants. Notably, the recycled IE also provides an efficient conductive filler for transparent ionic papers, which can be used to design soft transparent triboelectric nanogenerators for energy harvesting and multidirectional motion sensing. This work creates a new direction for future research involving intelligent soft electronics.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
