Nature abounds with intricate composite architectures composed of hard and soft materials synergistically intertwined to provide both useful functionality and mechanical integrity. Recent synthetic efforts to mimic such natural designs have focused on nanocomposites, prepared mainly by slow procedures like monomer or polymer infiltration of inorganic nanostructures or sequential deposition. Here we report the self-assembly of conjugated polymer/silica nanocomposite films with hexagonal, cubic or lamellar mesoscopic order using polymerizable amphiphilic diacetylene molecules as both structure-directing agents and monomers. The self-assembly procedure is rapid and incorporates the organic monomers uniformly within a highly ordered, inorganic environment. Polymerization results in polydiacetylene/silica nanocomposites that are optically transparent and mechanically robust. Compared to ordered diacetylene-containing films prepared as Langmuir monolayers or by Langmuir-Blodgett deposition, the nanostructured inorganic host alters the diacetylene polymerization behaviour, and the resulting nanocomposite exhibits unusual chromatic changes in response to thermal, mechanical and chemical stimuli. The inorganic framework serves to protect, stabilize, and orient the polymer, and to mediate its function. The nanocomposite architecture also provides sufficient mechanical integrity to enable integration into devices and microsystems.

Seeding and autocatalytic reduction of platinum salts in aqueous surfactant solution using ascorbic acid as the reductant leads to remarkable dendritic metal nanostructures. In micellar surfactant solutions, spherical dendritic metal nanostructures are obtained, and the smallest of these nanodendrites resemble assemblies of joined nanoparticles and the nanodendrites are single crystals. With liposomes as the template, dendritic platinum sheets in the form of thin circular disks or solid foamlike nanomaterials can be made. Synthetic control over the morphology of these nanodendrites, nanosheets, and nanostructured foams is realized by using a tin-porphyrin photocatalyst to conveniently and effectively produce a large initial population of catalytic growth centers. The concentration of seed particles determines the ultimate average size and uniformity of these novel two- and three-dimensional platinum nanostructures.

Twin carbon nanocoils (T-CNCs) were synthesized by means of acetylene decomposition over nickel nanoparticles. From the TEM image, one can see the growth of carbon nanocoils from the opposite sides of a nickel nanodisc, making an interangle of 180 degrees. We examined the microwave electromagnetic (EM) and microwave-absorbing properties of the as-prepared and annealed (1400 degrees C in Ar) T-CNCs systematically. A composite containing the as-prepared T-CNCs (15 wt %) and paraffin exhibited strong microwave absorption in a frequency range of 2 to 18 GHz. Over an absorber of double-layered composite (2.5 and 3.5 nim thickness), an absorption bandwidth of ca. 10 GHz corresponding to reflection loss below -10 dB can be obtained. We found that the magnetic parameters of the composite are low and suggest that the good absorption properties of T-CNCs should be attributed to dielectric rather than magnetic loss. It was observed that the as-prepared T-CNCs are superior to the annealed T-CNCs in microwave absorption ability, and such a phenomenon is interpreted in terms of the defect and graphitic nature of the materials. We also demonstrated that the complex permittivity and electric conductivity of T-CNCs can be controlled via annealling of T-CNCs at high temperature

ZnS:Cu nanocrystals were synthesized in polymeric networks. X-ray photoemission spectroscopy and atomic absorption data show that the Zn and Cu ion mass contents were about 8.2% and 0.12%, respectively. The particle size of ZnS:Cu nanocrystals was about 3.0 nm, measured by UV-vis spectrum. Due to the quantum size effects, the band gap energy of ZnS nanocrystals was about 4.2 eV. Compared with the photoluminescence of ZnS which peaks at 390 nm, the photoemission of ZnS:Cu/polymer thin films was peaking at 415 nm because of Cu acting as luminescent centers. The ZnS:Cu/polymer was also used to fabricate light-emitting diode (LED), as the emitting layer of LED, the blue light of electroluminescence was observed at room temperature, and its turn-on voltage was less than 4 V.

Conjugated polymer/silica nanocomposites with hexagonal, cubic, or lamellar mesoscopic order were synthesized by self-assembly using polymerizable amphiphilic diacetylene molecules as both structure-directing agents and monomers. The self-assembly procedure is rapid and incorporates the organic monomers uniformly within a highly ordered, inorganic environment. By tailoring the size of the oligo(ethylene glycol) headgroup of the diacetylene-containing surfactant, we varied the resulting self-assembled mesophases of the composite material. The nanostructured inorganic host altered the diacetylene polymerization behavior, and the resulting nanocomposites show unique thermo-, mechano-, and solvatochromic properties. Polymerization of the incorporated surfactants resulted in polydiacetylene (PDA)/silica nanocomposites that were optically transparent and mechanically robust. Molecular modeling and quantum calculations and (13)C spin-lattice relaxation times (T(1)) of the PDA/silica nanocomposites indicated that the surfactant monomers can be uniformly organized into precise spatial arrangements prior to polymerization. Nanoindentation and gas transport experiments showed that these nanocomposite films have increased hardness and reduced permeability as compared to pure PDA. Our work demonstrates polymerizable surfactant/silica self-assembly to be an efficient, general approach to the formation of nanostructured conjugated polymers. The nanostructured inorganic framework serves to protect, stabilize, and orient the polymer, mediate its performance, and provide sufficient mechanical and chemical stability to enable integration of conjugated polymers into devices and microsystems.

Crystalline helical carbon nanotubes (HCNTs) are synthesized as the main products in the pyrolysis of acetylene at 450 °C over Fe nanoparticles generated by means of a combined sol–gel/reduction method. Transmission electron microscopy (TEM) images reveal that there are two HCNTs attached to each Fe3C nanoparticle, and that the two HCNTs are mirror images of each other. Annealing in Ar at 750 °C and purification by immersion in hot (90 °C) HCl solution do not significantly change the structure of the HCNTs, despite the partial removal of Fe nanoparticles by the latter treatment. The magnetic properties of the as‐prepared, annealed, and purified HCNTs have been systematically examined. The annealed sample shows relatively high magnetization due to the ferromagnetic α‐Fe nanoparticles encapsulated in the HCNT nodes. In the case of HCl treatment, relatively pure HCNTs are obtained by the removal of ferromagnetic nanoparticles from the double‐HCNT nodes. The effects of the amount of catalyst used in the synthesis process on the morphology and yield of the carbon products have also been investigated.

Graphene has evoked extensive interests for its abundant physical properties and potential applications. It is reported that the interfacial electronic interaction between metal and graphene would give rise to charge transfer and change the electronic properties of graphene, leading to some novel electrical and magnetic properties in metal-graphene heterostructure. In addition, large specific surface area, low density and high chemical stability make graphene act as an ideal coating material. Taking full advantage of the aforementioned features of graphene, we synthesized graphene-coated Fe nanocomposites for the first time and investigated their microwave absorption properties. Due to the charge transfer at Fe-graphene interface in Fe/G, the nanocomposites show distinct dielectric properties, which result in excellent microwave absorption performance in a wide frequency range. This work provides a novel approach for exploring high-performance microwave absorption material as well as expands the application field of graphene-based materials.

of the 2D structures has approached its limit (< 90%) due to which the energy loss via reflection (2-5%) and thermal radiation heat loss (8-12%) occurs in all the 2D structures.One of the effective strategies for further improving the vapor-generation efficiency is to decrease the surface temperature of the absorber by increasing the surface area within a given projection area. [22] Some unprecedented vapor-generation rates have been reported in various 3D generators, which are all beyond the input solar energy limit. [23][24][25] Here, we have found that bamboos, as a natural hierarchical cellular material, can be excellent 3D solar vapor-generation devices due to their unique structural features. By a simple carbonization progress, the bamboos maintain remarkable mechanical property. Meanwhile, the carbonized bamboo-based evaporator possesses the following advantages: 1) natural hydrophilicity; 2) numerous aligned microchannels acting as highways for rapid water transport; 3) high light absorptance in a broad spectral range; 4) reduced thermal radiation heat loss; 5) lower average temperature than environment; 6) reduced vaporization enthalpy of water confined in the bamboo mesh; 7) remarkable mechanical properties; 8) ability of salt self-cleaning; 9) good scalability and low cost. As a result, a floating carbonized bamboo sample can evaporate water with an extremely high vapor-generation rate of 3.13 kg m −2 h −1 under 1 sun illumination. It also shows superior reusability and stability for solar vapor generation, without any performance degradation after cycling 360 h. The carbonized bamboo shows favorable overall performance compared with other reported solar vapor generators and has attractive applications in desalination as well asindustrial and domestic wastewater abatement. All of these features are elucidated below in detail.Bamboo is the fastest-growing and highest-yielding hierarchical cellular material on the Earth. A typical bamboo reaches maturity within months and ultimate mechanical properties within few years, making it one of the most renewable resources. [26] Figure 1a-c shows the illustration of the design concept for a bamboo-based solar vapor-generation device. Bamboo tubes with desired height were cut from the natural bamboo and were carbonized to make it dark. The carbonized Given the global challenges of water scarcity, solar-driven vapor generation has become a renewed topic as an energy-efficient way for clean water production. Here, it is revealed that bamboo, as a natural hierarchical cellular material, can be an excellent 3D solar vapor-generation device by a simple carbonization progress. A floating carbonized bamboo sample evaporates water with an extremely high vapor-generation rate of 3.13 kg m −2 h −1 under 1 sun illumination. The high evaporation rate is achieved by the unique natural structure of bamboos. The inner wall of bamboo recovers the diffuse light energy and the thermal radiation heat loss from the 3D bamboo bottom, and the outer wall captures energy from the warmer...