Hydrophobic Interface Starch Nanofibrous Film for Food Packaging: From Bioinspired Design to Self-Cleaning Action.

Starch-derived edible food films have great potential as biodegradable food packaging materials because they reduce the overuse of traditional petroleum-based plastic. Herein, we demonstrate a direct method of mass producing a pure starch food packaging film that consisted of starch nanofibers by using a temperature-assisted electrospinning technique without addition of any nonstarch components. To overcome the major issue of ultralow hydrophobicity of starch nanofibrous film (SNF), we used a facile and low-cost solution immersion approach to create a fiber coating of stearic acid (STA) inspired by biological organisms with superhydrophobic properties, such as lotus leaves. Hierarchical flower-like micronanostructures were obtained on SNF by controlled assembly of STA onto the surface of starch nanofibers. Benefiting from the effective formation of STA self-assembled lamella, the multiscale microstructure surface features, low surface energy, and enhancing thermal stability of SNF were obtained and confirmed to result in the variety of its hydrophobicity, which can be also tailored by simple controlling of the solution concentration of STA. Importantly, the STA-self-assembled coated SNF enabled water to roll freely in all directions, which is a crucial factor for self-cleaning. Our novel strategy based on self-assembly can guide development of bioinspired hydrophobic interfaces for starch-based films for edible hydrophobic materials.

Promising Rice-Husk-Derived Carbon/Ni(OH)2 Composite Materials as a High-Performing Supercapacitor Electrode.

Improving the electrochemical performance of biomass-derived carbon electrode-active materials for supercapacitor applications has recently attracted considerable attention. Herein, we develop hybrid electrode materials from rice-husk-derived porous carbon (RH-C) materials and ß-Ni(OH)2 via a facile solid-state reaction strategy comprising two steps. The prepared RH-C/Ni(OH)2 (C-Ni) was investigated using scanning electron microscopy (SEM) (energy-dispersive X-ray spectrometer (EDS)), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) to acquire the physical and chemical information, which was used to demonstrate the successful fabrication of C-Ni. Thermogravimetric analysis (TGA) measurement results confirmed that the thermal stability of C-Ni changed due to the presence of Ni(OH)2. As expected, C-Ni possesses a high capacitance of ∼952 F/g at a current density of 1.0 A/g. This result is higher than that of pure biomass-based carbon materials under the three-electrode system. This facile preparation method, which was used to synthesize the electrode-active materials, can extend to the value-added utility of other waste biomass materials as high-performing supercapacitor electrodes for energy storage applications.

Polysaccharide-Based Hydrogels Derived from Cellulose: The Architecture Change from Nanofibers to Hydrogels for a Putative Dual Function in Dye Wastewater Treatment.

Agricultural production-caused water contamination has become an urgent environmental issue that has drawn much attention in recent years. One such contamination case is the environmental disposal of colored effluents from the food processing industry (i.e., food dyes). Effective methods for removing dye contaminants from water have been increasingly sought, and different adsorbents have been developed for this purpose. Here, polysaccharide-based hydrogels derived from cellulose were constructed and used in the removal of methylene blue (MB) (as the representative dye) from an aqueous medium (as simulated dye liquor wastewater). To improve the purification efficiency, TiO2 nanoparticles were encapsulated into cellulose nanofibers, which were consequently changed to hydrogels with respective advantages. The morphology, chemical composition, and structure of the as-prepared polysaccharide-based hydrogels and the transformation process from nanofibers to hydrogels were revealed by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction, and the presence of a gel network structure and TiO2 nanoparticles was confirmed. As expected, the polysaccharide-based hydrogels exhibited good MB removal performance because of their synergistic effects of absorption and photocatalytic degradation. Furthermore, the cell cytotoxicity test showed that the polysaccharide-based hydrogels possessed good biocompatibility. The facile, noncytotoxic, and general strategy presented here could be extended to the preparation of other polysaccharide-based hydrogel materials and has good prospects for application in wastewater treatment.