Search

Polymer-tethered nanoparticles with different geometric shapes are very useful fillers of polymer nanocomposites. Herein, a universal approach for the fabrication of such nanoparticles with precisely controlled shape and composition is reported. By microphase separation of poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene (PTEPM-b-PS) in the presence of oligomers, o-TEPM (oT) and/or o-S (oS), followed by cross-linking and dispersion in PS solvent, precisely tailored PS-grafted nanoparticles were prepared. These particles include those with varied shapes but identical PS shells, particles with varied core sizes but the same PS shell, and particles with fixed shapes but varied PS shells. These particles are ideal model nanofillers to study the dynamics and reinforced mechanism of polymer nanocomposites.

The large-scale preparation of ultralarge graphene oxide (ULGO) is urgently needed for developing advanced devices and high-performance nanocomposites. However, it is extremely difficult to produce ULGO in an industrially viable, high-efficiency manner because of the inevitable sheet fragmentation and significant gelation behavior occurred in existing methods. We propose a stationary oxidation-monolithic crystalline swelling strategy that can completely convert graphite to ULGO. This new stationary oxidation method minimizes the sheet fracture and prevents the exfoliation of oxidized layers without sacrificing the oxidation rate, resulting in oxidized flakes with high crystalline and lateral sizes the same as raw graphite. The oxidized graphite flakes undergo a monolithic crystalline swelling during the purification, leading to the formation of a three-dimensional ordered structure without peeling. This enables graphite oxide to be purified by spontaneous sedimentation within 1 h as gelation is avoided an...

Design and fabrication of the micro/nanostructures of the network units is a critical issue for porous nanonetwork structured materials. Significant progress has been attained in construction of the network units with zero-dimensional spherical shapes. However, owing to the limitations of synthetic methods, construction of porous building blocks in one dimension featuring high aspect ratios for porous nanonetwork structured polymer (PNSP) remains largely unexplored. Here we present the successful design and preparation of PNSP with a novel type of one-dimensional network unit, i.e., microporous heterogeneous nanowire. Well-defined core-shell polymer nanoobjects prepared from a gelable block copolymer, poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene are employed as building blocks, and facilely transformed into PNSP via hypercrosslinking of polystyrene shell. The as-prepared PNSP exhibits unique three-dimensional hierarchical nanonetwork morphologies with large surface area. These findings could provide a new avenue for fabrication of unique well-defined PNSP, and thus generate valuable breakthroughs in many applications.

A PDMS elastomer based on acylhydrazone groups with both acid- and heat-assisted self-healing properties was successfully prepared from tetra-acylhydrazine-terminated PDMS and terephthalaldehyde through solution casting. The good healing performance was obtained with catalytic acetic acid for 24 h at 25 °C or by annealing at 120 °C for 2 h. The elastomer exhibited a reversible transition near 80 °C observed by rheological measurements and variable-temperature FTIR, which corresponded to the dissociation and reconstruction of hydrogen bonds between acylhydrazone groups. Since the non-equimolar sample presented similar behaviors with the equimolar sample, it verifies that the reversible dissociation/reformation of hydrogen bonds dominates the heat-assisted self-healing process. This finding will enable better understanding of the contribution of hydrogen bonding interactions in acylhydrazone self-healing systems, thus promoting the development of self-healing bulk materials based on acylhydrazone groups.

The manufacturing of three-dimensional (3D) graphene monolith with high mechanical and electrical performance has become an urgent issue in view of their potential applications in energy and electronics fields. Due to the structure rigidity and poor liquid-phase processing capability of graphene sheets, it is challenging to fabricate 3D graphene monolith with high mechanical performance, including strength, toughness and resiliency. Graphene oxide (GO) shows an improved dispersibility and reduction-restorable conductivity, which enables it to effectively balance the processing and comprehensive performances of graphene monolith. Here, we demonstrate a strategy to fabricate high-performance, shape-designable 3D graphene monolith through a 3D printing method based on large-sized graphene oxide (LGO) fluid ink. The concentration of the LGO ink for printing is as low as 20 mg/mL. The resulting monolith exhibits low density (12.8 mg/cm3), high electrical conductivity (41.1 S/m), high specific strength (10.7 × 103 N·m/Kg) and compressibility (up to 80% compressive strain). Such a 3D printing technique enables plenty of complicated monolith structures and broadens the application range of graphene.

Silver nanowire (Ag NW) based films are considered as a promising alternative for traditional indium tin oxide but still suffer from some limitations, including insufficient conductivity, transparency and environmental instability. We here report a novel etching synthesis strategy to improve the performance of Ag NW films. Different from the traditional methods to synthesize high aspect ratios of NWs or employ electrically conductive coatings, we find it effective to reduce the high-reactivity defects of NWs for optimizing the comprehensive performance of Ag NW films. In this strategy etching can suppress the generation of high-reactivity defects and meanwhile the etching growth of NWs can be accomplished in an uneven ligand distribution environment. The resulting Ag NWs are uniformly straight with a sharp-edged structure. The transparent conductive film obtained exhibits simultaneous improvements in electrical conductivity, transparency and air stability. Even after exposure in air for 200 days and no protective coatings, the film can still meet the highest requirement of practical applications, with a figure of merit 361 (i.e., FoM > 350). These results not only demonstrate the importance of defect control in the synthesis of Ag NWs, but also pave a way for further optimizing the performance of Ag NW-based films.