Reactive Template-Induced Self-Assembly to Ordered Mesoporous Polymeric and Carbonaceous Materials

As an important method for preparing ordered mesoporous polymeric and carbonaceous materials, the organic template directed self-assembly is facing challenges because of the weak noncovalent interactions between the organic templates and the building blocks. Herein we develop a novel reactive template-induced self-assembly procedure for fabrication of ordered mesoporous polymer and carbon materials. In our approach, the aldehyde end-group of reactive F127 template can react with the resol building block to <i>in-situ</i> form a stable covalent bond during the self-assembly process. This is essential for an enhanced interaction between the resol and the template, thus leading to the formation of an ordered body-centered cubic mesostructure. We also show that the ordered mesoporous carbon product exhibits superior capacitive performance, presenting an attractive potential candidate for high performance supercapacitor electrodes

Fabrication, Characterization, and Biocompatibility of Polymer Cored Reduced Graphene Oxide Nanofibers

Graphene nanofibers have shown a promising potential across a wide spectrum of areas, including biology, energy, and the environment. However, fabrication of graphene nanofibers remains a challenging issue due to the broad size distribution and extremely poor solubility of graphene. Herein, we report a facile yet efficient approach for fabricating a novel class of polymer core-reduced graphene oxide shell nanofiber mat (RGO–CSNFM) by direct heat-driven self-assembly of graphene oxide sheets onto the surface of electrospun polymeric nanofibers without any requirement of surface treatment. Thus-prepared RGO–CSNFM demonstrated excellent mechanical, electrical, and biocompatible properties. RGO–CSNFM also promoted a higher cell anchorage and proliferation of human bone marrow mesenchymal stem cells (hMSCs) compared to the free-standing RGO film without the nanoscale fibrous structure. Further, cell viability of hMSCs was comparable to that on the tissue culture plates (TCPs) with a distinctive healthy morphology, indicating that the nanoscale fibrous architecture plays a critically constructive role in supporting cellular activities. In addition, the RGO–CSNFM exhibited excellent electrical conductivity, making them an ideal candidate for conductive cell culture, biosensing, and tissue engineering applications. These findings could provide a new benchmark for preparing well-defined graphene-based nanomaterial configurations and interfaces for biomedical applications

Biocompatible, Free-Standing Film Composed of Bacterial Cellulose Nanofibers–Graphene Composite

In recent years, graphene films have been used in a series of wide applications in the biomedical area, because of several advantageous characteristics. Currently, these films are derived from graphene oxide (GO) via chemical or physical reduction methods, which results in a significant decrease in surface hydrophilicity, although the electrical property could be greatly improved, because of the reduction process. Hence, the comprehensive performance of the graphene films showed practical limitations in the biomedical field, because of incompatibility of highly hydrophobic surfaces to support cell adhesion and growth. In this work, we present a novel fabrication of bacterial cellulose nanofibers/reduced graphene oxide (BC-RGO) film, using a bacterial reduction method. Thus-prepared BC-RGO films maintained excellent hydrophilicity, while electrical properties were improved by bacterial reduction of GO films in culture. Human marrow mesenchymal stem cells (hMSCs) cultured on these surfaces showed improved cellular response with higher cell proliferation on the BC-RGO film, compared to free-standing reduced graphene oxide film without the nanoscale fibrous structure. Furthermore, the cellular adhesion and proliferation were even comparable to that on the tissue culture plate, indicating that the bacterial cellulose nanofibers play a critically contructive role in supporting cellular activities. The novel fabrication method greatly enhanced the biochemical activity of the cells on the surface, which could aid in realizing several potential applications of graphene film in biomedical area, such as tissue engineering, bacterial devices, etc

Additional file 1: of Polyaniline-Coated Activated Carbon Aerogel/Sulfur Composite for High-performance Lithium-Sulfur Battery

Supporting information. Figure S1. TEM images of (a) ACA-500-S and the corresponding elemental mapping for (b) carbon, (c) sulfur, (d) oxygen. Figure S2. STEM images of (a) ACA-500-S@PANi and the corresponding elemental mapping for (b) carbon, (c) nitrogen, (d) sulfur, and (d) oxygen. Figure S3. The total XPS spectra of (a) ACA-500-S, (b) C 1s, and (c) S 2p spectra of ACA-500-S. The peaks at 164.0 and 165.2 eV in (c) indicate that the uniformly encapsulated sulfur exists in the form of elemental sulfur. Figure S4. (a) The total XPS spectra and (b) N 1s spectrum of ACA-500-S@PANi. Figure S5. Discharge-charge curves at various rates for (a) ACA-500-S@PANi and (b) ACA-500-S cathodes. Figure S6. Discharge-charge curves recorded at different cycles for (a) ACA-500-S@PANi and (b) ACA-500-S cathodes at 1C. Figure S7. TGA curves of (a) ACA-500-S-70% (black), ACA-500-S@PANi-61% (blue), and ACA-500-S@PANi-55% (red) and (b) ACA-500-S-54% (violet) and ACA-500-S@PANi-45% (olive). Figure S8. (a) Rate performances of ACA-500-S-54% and ACA-500-S@PANi-55% cathodes. Discharge-charge curves at various rates for (b) ACA-500-S@PANi-55% and (c) ACA-500-S-54% cathodes. (d) Cycle performances of ACA-500-S@PANi-45% and ACA-500-S@PANi-61% cathodes at 1C. Table S1. Textual characteristic of ACA-500, ACA-500-S, and ACA-500-S@PANi. Table S2. Summary of cycle stability performances of representative conductive PANi coating for carbon/S cathodes at 1 C rate. (DOCX 980 kb

Preparation of Polymeric Nanoscale Networks from Cylindrical Molecular Bottlebrushes

The design and control of polymeric nanoscale network structures at the molecular level remains a challenging issue. Here we construct a novel type of polymeric nanoscale networks with a unique microporous nanofiber unit employing the intra/interbrush carbonyl cross-linking of polystyrene side chains for well-defined cylindrical polystyrene molecular bottlebrushes. The size of the side chains plays a vital role in the tuning of nanostructure of networks at the molecular level. We also show that the as-prepared polymeric nanoscale networks exhibit high specific adsorption capacity per unit surface area because of the synergistic effect of their unique hierarchical porous structures. Our strategy represents a new avenue for the network unit topology and provides a new application for molecular bottlebrushes in nanotechnology

Water-Dispersible, Responsive, and Carbonizable Hairy Microporous Polymeric Nanospheres

Multifunctionalization of microporous polymers is highly desirable but remains a significant challenge, considering that the current microporous polymers are generally hydrophobic and nonresponsive to different environmental stimuli and difficult to be carbonized without damage of their well-defined nanomorphology. Herein, we demonstrate a facile and versatile method to fabricate water-dispersible, pH/temperature responsive and readily carbonizable hairy microporous polymeric nanospheres based on combination of the hyper-cross-linking chemistry with the surface-initiated atom transfer radical polymerization (SI-ATRP). The hyper-cross-linking creates a highly microporous core, whereas the SI-ATRP provides diverse functionalities by surface grafting of hairy functional blocks. The as-prepared materials present multifunctional properties, including sensitive response to pH/temperature, high adsorption capacity toward adsorbates from aqueous solution, and valuable transformation into well-defined microporous carbon nanospheres because of hybrid of carbonizable core and thermo-decomposable protection shell. We hope this strategy could promote the development of both functional microporous polymers and advanced hairy nanoparticles for multipurpose applications

Mechanochemistry: A Green, Activation-Free and Top-Down Strategy to High-Surface-Area Carbon Materials

Renewable resources (e.g., agricultural byproducts) are widely used in the production of commercial activated carbon, but the activation procedures still have serious drawbacks. Here we develop a green, activation-free, top-down method to prepare high-surface-area carbon materials from agricultural wastes through mechanochemistry. The facile mechanochemical process can smash the monolithic agricultural wastes into tiny microparticles with abundant surfaces and bulk defects, which leads to the generation of well-developed hierarchical porous structures after direct carbonization. The as-obtained carbon materials simultaneously present high surface areas (1771 m² g^–1) and large pore volumes (1.88 cm³ g^–1), and thus demonstrate excellent electrochemical performances as the interlayer for lithium–sulfur batteries and much superior creatinine adsorption capabilities to the medicinal charcoal tablets. These results provide a new direction for fabricating high-surface-area porous materials without any toxic reagents or complicated activation procedures, and can spur promising electrochemical and medical applications