Nanomaterials Research with a Chinese Flavor

Last July 2–4, we had a successful meeting—the 4th Sino-US Nano Workshop—at the University of Science and Technology of China (USTC) in Hefei, Anhui. This event brought together more than 40 scientists both from the United States and China to exchange information related to nanomaterials research. Our guests also include Dr. David Flanagan, the Editor in Chief of Advanced Functional Materials, who gave a wonderful talk on writing and publishing of scientific papers. We had a three-full-day program devoted to the synthesis of functional nanomaterials and their applications in areas as diverse as biomedical research, energy, electronics, photonics, and photovoltaics. Some of the speakers were invited to contribute to a Special Issue published in Advanced Materials (Issue 17, May 4, 2010) that was purposely focused on Materials Research by USTCers. To reflect the diversity of nanomaterials research by Chinese scientists, we decided to publish this accompanying Special Issue, with contributions mainly from representative speakers at the workshop. This issue begins with an essay by K. Chen from the Department of Engineering and Materials, the National Natural Science Foundation of China (NSFC). He gives an overview of the current status for materials research in China, with a focus on both inorganic and nonmetallic materials. He also highlights a number of important contributions from Chinese scientists in areas of traditional advanced materials and nanomaterials over the past decade. For the synthesis of nanomaterials, Z. Xie, L. Zheng, and co-workers review recent progress in the synthesis of inorganic nanocrystals with high-energy facets and their potential applications in photoluminescence, gas sensing, and catalysis. Y. Sun reviews advances in the synthesis of noble-metal nanoplates on semiconductor substrates and their applications in catalysis and surface-enhanced Raman scattering. D. Zhao and co-workers demonstrate the synthesis of ordered mesoporous carbon with pore sizes tunable in the range of 12–33 nm and wall thickness of 5–11 nm by using amphiphilic diblock copolymers as templates and through the evaporation-induced self-assembly process. Y. Xie and co-workers report on the synthesis of Ag1.2V3O8, a room-temperature ferromagnetic material, by controlling the oxidation of the V4+ precursor in a solution containing Ag+ ions. Nano­structures of this material are expected to find applications in spintronics. D. Pang and co-workers present a new route to the synthesis of water-soluble, glutathione-capped gold clusters with a mean diameter of 1.3 nm through biomimetic reduction in a quasi-biological system containing electrolytes, peptides, and coenzymes. L. Guo and co-workers describe the synthesis of peapod-like Ni/Ni3S2 nanochains and nickel sulfide hollow chains, as well as their magnetic properties. For the biomedical applications, J. Chen, Y. Xia, and co-workers review advances in gold nanocages—a novel class of multifunctional nanomaterials attractive as theranostic agents for cancer diagnosis and treatment. H.-W. Sung and co-workers review recent progress in the development of a nanoparticle-based system for oral delivery of drugs. Besides insulin, this carrier system is expected to serve as a universal platform for oral delivery of hydrophilic macromolecules such as pharmaceutically active peptides/proteins, glycosaminoglycans, and oligonucleotides. S. H. Yu and co-workers report a new method for the synthesis of multicomponent Ni7Co3 alloy-Au nano­rings at room temperature and in water by using metallic Ni7Co3 alloy nanorings as both reducing agent and sacrificial template, as well as their application as multimodal imaging contrast agents for cancer diagnosis. C. H. Yan and co-workers report the synthesis of YVO4:Eu nanoparticles using an efficient, one-pot method and their application as versatile luminescent bioprobes for in vitro detection. X. Y. Jiang and co-workers describe a novel method that combines microfluidic channels and holey poly(dimethyl siloxane) (PDMS) membranes for patterning multiple types of cells on a variety of substrates including those bearing micro- and nano-scale structures. This work will provide a new approach for studying many processes in vitro that involve cell-cell and/or cell-substrate interactions. X. Gao and co-workers report a new method for encapsulating quantum dot (QD) barcodes with silica shells to greatly improve their dispersibility and stability. This new method will be able to solve some of the key problems in QD barcoding technology such as nanoparticle leaching. For the energy-related applications, J. Fang and co-workers report a facile and reliable method for the synthesis of high-quality Pt3Fe nanocubes. The surface structures of these alloy nano­crystals were found to play an important role in determining the catalytic activity. These results highlight the significance of controlling the shape of a catalyst as an approach to improve its performance. H. Yang and co-workers describe a new route to the synthesis of Pt-surface rich heterogeneous alloy nanoparticles through selective electrochemical dissolution of silver from platinum-silver alloy nanoparticles. These Pt-surface rich PtAg alloy nanoparticles exhibited much higher activity than Pt nanoparticles as electrocatalysts in formic acid oxidation reaction. Y. Yan and co-workers report on the synthesis of porous platinum nanotubes and their applications as electrocatalysts for oxygen reduction and methanol oxidations. The porous platinum nanotubes were demonstrated with greatly improved mass and specific activity towards oxygen reduction than the conventional catalyst. Y. Li and co-workers report an ionic liquid-assisted method for the preparation of highly-dispersed and uniform noble metal nanoparticles with tunable sizes supported on MWCNTs, which show enhanced electrocatalytic activity and stability towards methanol oxidation, as well as remarkably size-dependent catalytic activity and selectivity for glycerol oxidation. For applications in electronics, photonics, and sensing, L. Jiang and co-workers review a number of techniques that have been developed to switch the adhesion on a liquid/solid interface, including tuning the surface chemical composition, tailoring the surface morphology, and applying external stimuli. A general guideline on how to fabricate superhydrophobic surfaces with reversible switching between low and high adhesion to water droplets in response to external stimuli are also presented. W. Cai and co-workers review recent progresses in the fabrication of ordered, controllably micro/nanostructured porous films based on monolayer colloidal crystal template and solution dipping, as well as their application for sensor fabrication. L. Qi and co-workers report a facile method for fabrication of two-dimensionally ordered macroporous silver thin films and their application in molecular sensing. B. Yang and co-workers report the fabrication of a new class of bio-inspired, water vapor responsive organic/inorganic hybrid one-dimensional photonic crystals with tunable full color stop bands, and their application in sensing. G. Meng and co-workers report a new method for construction of branched and multi-generation branched architectures of silicon nanotubes and metal nanowires via filling the nanochannels in anodic aluminum oxide templates by pyrolysis of silane and electrodeposition of metals. Z. Zhang and co-workers report their findings on the axial compression of CNT fibers embedded in epoxy with the assistance of in situ Raman spectroscopy, revealing that the conspicuous stiffening and strengthening effects of the embedded CNT fiber are dominated by the CNT architecture within the fiber. As limited by space, we are unable to include the work by all invited speakers at the workshop. We hope this Special Issue will provide a window for scientists working in the field of nanomaterials to learn more about the work being conducted by their Chinese colleagues and serve as a platform to promote mutual collaboration in the future.