Papers with nanoscaled surface roughness and hydrophobically modification have been widely used in daily life. However, the relatively complex preparation process, high costs and harmful compounds have largely limited their applications. This research aims to fabricate superhydrophobic papers with low cost and nontoxic materials. The surface of cellulose fibers was initially coated with a film of SiO2 nanoparticles via sol-gel process. After papermaking and subsequent modification with hexadecyltrimethoxysilane through a simple solution-immersion process, the paper showed excellent superhydrophobic properties, with water contact angles (WCA) larger than 150°. Moreover, the prepared paper also showed superior mechanical durability against 10 times of deformation. The whole preparation process was carried out in a mild environment, with no intricate instruments or toxic chemicals, which has the potential of large-scale industrial production and application.
Traditional wound dressings have some major deficiencies, including poor antibacterial ability, low exudate absorption rate and dry environment. These defects can be addressed by the prepared hydrogels in this study, which can provide a moist and cool environment for wound healing. Polyvinyl alcohol‐chitosan/cerium (PVA‐Cs/Ce) composite hydrogels are prepared by a freeze‐thaw method and characterized by x‐ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the effects of chitosan/cerium (Cs/Ce) complexes with different contents on properties, including mechanical properties, water vapor permeability, swelling ratio, and thermal stability are investigated. SEM images indicate that the composite hydrogels have a good three‐dimensional pore structure. Compared with the pure PVA hydrogel, the composite hydrogels show better swelling properties and more suitable water vapor transmission rate (2504 g m‐2·day) by adding Cs/Ce complexes. And the elongation at break of the hydrogel with a ratio of 5:3 (PVA: Cs/Ce) is the highest value of 567%. In the bacteriostatic circle experiment, PVA‐Cs/Ce composite hydrogels exhibit a pronounced inhibitory effect against two bacteria (Staphylococcus aureus and Escherichia coli). These results suggest that these composite hydrogels have great potential as wound dressings.
Carbon quantum dots (CQDs) are one of the most promising luminescent nanomaterials for anti‐counterfeiting due to their excellent optical properties, low toxicity, and environmental friendliness. With the development of green chemistry, biomass carbon sources have attracted attention. Herein, nitrogen‐doped carbon quantum dots (N‐CQDs) are synthesized using waste corn bract nanocellulose as the carbon source and L‐histidine as the nitrogen source in a simple and quick one‐step microwave method. It is found that a raw material mass ratio of 1:4, a temperature of 100 °C, and a preparation time of 5 min are the optimum preparation conditions. The fluorescence quantum yield of N‐CQDs obtained under these conditions is 32.64%. Under the excitation of light at a wavelength of 365 nm, the emission peak of N‐CQDs is located at 430 nm and emits blue light. This study also provides a method to prepare fluorescent anti‐counterfeiting films with excellent performance and fluorescent detection probes solely from waste biomass corn bract leaves and L‐histidine.
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