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Self-assembly Method (self-assembly + method)
Selected AbstractsA Controllable Self-Assembly Method for Large-Scale Synthesis of Graphene Sponges and Free-Standing Graphene FilmsADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Fei Liu Abstract A simple method to prepare large-scale graphene sponges and free-standing graphene films using a speed vacuum concentrator is presented. During the centrifugal evaporation process, the graphene oxide (GO) sheets in the aqueous suspension are assembled to generate network-linked GO sponges or a series of multilayer GO films, depending on the temperature of a centrifugal vacuum chamber. While sponge-like bulk GO materials (GO sponges) are produced at 40,°C, uniform free-standing GO films of size up to 9,cm2 are generated at 80,°C. The thickness of GO films can be controlled from 200,nm to 1,µm based on the concentration of the GO colloidal suspension and evaporation temperature. The synthesized GO films exhibit excellent transparency, typical fluorescent emission signal, and high flexibility with a smooth surface and condensed density. Reduced GO sponges and films with less than 5,wt% oxygen are produced through a thermal annealing process at 800,°C with H2/Ar flow. The structural flexibility of the reduced GO sponges, which have a highly porous, interconnected, 3D network, as well as excellent electrochemical properties of the reduced GO film with respect to electrode kinetics for the [Fe(CN)6]3,/4, redox system, are demonstrated. [source] Dendrimer-Functionalized Iron Oxide Nanoparticles for Specific Targeting and Imaging of Cancer Cells,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007H. Wang Abstract We demonstrated a unique approach that combines a layer-by-layer (LbL) self-assembly method with dendrimer chemistry to functionalize Fe3O4 nanoparticles (NPs) for specific targeting and imaging of cancer cells. In this approach, positively charged Fe3O4 NPs (8.4,nm in diameter) synthesized by controlled co-precipitation of FeII and FeIII ions were modified with a bilayer composed of polystyrene sulfonate sodium salt and folic acid (FA)- and fluorescein isothiocyanate (FI)-functionalized poly(amidoamine) dendrimers of generation 5 (G5.NH2 -FI-FA) through electrostatic LbL assembly, followed by an acetylation reaction to neutralize the remaining surface amine groups of G5 dendrimers. Combined flow cytometry, confocal microscopy, transmission electron microscopy, and magnetic resonance imaging studies show that Fe3O4/PSS/G5.NHAc-FI-FA NPs can specifically target cancer cells overexpressing FA receptors. The present approach to functionalizing Fe3O4 NPs opens a new avenue to fabricating various NPs for numerous biological sensing and therapeutic applications. [source] Combinatorial Hierarchically Ordered 2D Architectures Self-assembled from Nanocrystal Building Blocks,ADVANCED MATERIALS, Issue 19 2008Xiangxing Xu A one-step, low-cost, and general nanocrystal self-assembly method that covers both the nanometer-scale superlattice and macroscale ordered patterns,that is, hierarchical architectures,is developed. This approach can generate various functional, compositional, and dimensional combinatorial architectures. It may give new opportunities in applications of catalysis, electronics, energy, magnetic devices, and bio-techniques. [source] The substituent effects on the structure and surface morphology of polyanilineJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Mutlu Sahin Abstract In this work, poly(2-fluoroaniline), poly(2-chloroaniline), poly(2-methylaniline), and poly(N -ethylaniline) were prepared by a self-assembly method using an oxidizing system consisting of a dopant anion, p-toluene sulfonate with ammonium peroxydisulfate. The effects of substituents on the surface morphology, conductivity, molecular weight, spectral and thermal properties of the polymers were studied. SEM results revealed that the surface morphology of the resulting polymers changed from nanofiber to spherical structure by changing the substituent on the aniline monomers. The structure and properties of these conducting films were characterized by FTIR, UV-vis, elemental analysis, TGA, conductivity, and cyclic voltammetry. The polymer films show electroactivity in monomer free solution. Molecular weight of the polymers was determined by gel permeation chromatography. The dry electrical conductivity values of the substituted-polyanilines were found to be lower than that of PANI. The results revealed that the molecular structures of the polymers were similar to those of the emeraldine form of polyaniline. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] | ||||||||||