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To meet the demand for clean water, solar-driven water evaporation has recently drawn growing attention due to the high efficiency and environment-friendly procedure. For the transportation of water, these evaporation devices mostly possess porous structures. However, for long-term use in the natural environment, it is highly required to prevent biofouling induced channel plugging due to the universal existence of microbes in the natural water. Herein, we fabricated a double-layered GO–chitosan/ZnO scaffold (GCZ scaffold) as the solar steam device. The upper GO aerogel layer serves as a solar thermal converter, while the lower chitosan/ZnO composite layer serves as a unidirectional water pump. This GCZ scaffold exhibits a high water evaporation rate and good solar energy conversion efficiency under 10 sun and one sun irradiations, respectively. Moreover, the embedding of ZnO nanoparticles in the lower chitosan layer effectively controls the formation of biofilms in the unidirectional channels, resulting in an anti-biofouling solar-driven water evaporator. Compared to the ZnO-free scaffold suffering from the biofouling induced channel plugging, this anti-biofouling GCZ scaffold maintains a high solar-driven water evaporation rate and efficiency (89.4% for E. coli and 89.7% for S. aureus) even after cultivating in the bacterial suspensions for 3 days. This anti-biofouling solar-driven water evaporator evidently improves the lifetime of the material in natural water, conducive to further commercial applications.

With the emerging of drug-resistant bacterial and fungal pathogens, there raise the interest of utilizing versatile antimicrobial biomaterials to treat the acute wound. Herein, we report the spraying mediated assembly of a bio-inspired Ag@reduced graphene-sodium alginate (AGSA) composite film for effective wound healing. The obtained film displayed lamellar microstructures similar to the typical “brick-and-mortar” structure in nacre. In this nacre-mimic structure, there are abundant interfacial interactions between nanosheets and polymeric matrix, leading to remarkable reinforcement. As a result, the tensile strength, toughness and Young’s modulus have been improved 2.8, 2.3 and 2.7 times compared with pure sodium alginate film, respectively. In the wound healing study, the AGSA film showed effective antimicrobial activities towards Pseudomonas aeruginosa, Escherichia coli and Candida albicans, demonstrating the ability of protecting wound from pathogenic microbial infections. Furthermore, in vivo experiments on rats suggested the effect of AGSA film in promoting the recovery of wound sites. According to MTT assays, heamolysis evaluation and in vivo toxicity assessment, the composite film could be applied as a bio-compatible material in vitro and in vivo. Results from this work indicated such AGSA film has promising performance for wound healing and suggested great potential for nacre-mimic biomaterials in tissue engineering applications.

High-performance composites containing various kinds of nanofibers as reinforcing building blocks have recently received considerable attention, owing to their superior mechanical properties. One of the effective strategies to reinforce these composites involves strengthening interfacial interactions via covalent bonds. However, in contrast to nanosheets, covalent bonds have been rarely used in nanofiber-reinforced composites. Herein, we report the macroscale fabrication of a series of Ag nanowire (NW)-thiolated chitosan (TCS) composite films via spray induced self-assembly. The obtained films were significantly strengthened by Ag–S covalent bonds formed between the Ag NWs and the thiol groups of TCS. The tensile strength of the optimized Ag NW-TCS film was up to 3.9 and 1.5 times higher compared with that of pure TCS and Ag NW-chitosan (CS) films, respectively.

Biomimetic assembly of high-quality nanosheets into nacre-like structures can produce macroscopic films with favorable mechanical and optical performances due to the intrinsic properties and high level of ordering of the nanoscale building blocks. Natural ground mica is abundant and exhibits great application potential. However, large size and low aspect ratio greatly limit its biomimetic assembly. Moreover, exfoliation of ground mica into high-quality nanosheets remains a significant challenge. Here, we report that large-scale exfoliation of ground mica into mono- or few-layered mica nanosheets with a production rate of ~1.0 g h−1 can be successfully achieved. The mica nanosheets are then assembled into strong biomimetic polymeric mica film that inherits the high electric insulation, excellent visible transmittance, and unique ultraviolet-shielding properties of natural mica. Its overall performance is superior to that of natural sheet mica and other biomimetic films, making the polymeric mica film a suitable substrate for flexible and transparent devices., Biomimetic assembly of nanosheets into nacre-like structures and films is of interest for a range of applications; the abundance of mica makes it a good candidate. Here, the authors report on the large-scale exfoliation of ground mica into nanosheets and the assembly into polymeric mica films.