Papers by Keyword: Self-Assemble

Abstract: Graphene aqueous dispersion is difficult to be prepared as conductive film by simple solvent evaporation deposition, not only because of the agglomeration in its aqueous solution, but also caused by the “coffee ring” phenomenon during solvent evaporation process. Herein, as a derivative of graphene, graphene oxide (GO) would be used as film forming material due to its good dispersion in aqueous solution and its liquid crystallinity. If GO can self-assemble as a compact pseudo-photonic crystal film by solvent evaporation deposition, it will be converted into a conducive graphene film after thermal reduction. In order to prepare a flexible and conductive elastomer material covered with graphene film, compact GO pseudo-photonic crystal film can be transferred onto the surface of a 10% stretched silicone rubber plate. After releasing the stretched force, GO pseudo-photonic crystal film can form a lot of folds, which provide allowance of shrinkage for this GO pseudo-photonic crystal film to avoid cracking during the high temperature reduction. Benefiting from transferring the GO film onto a stretched silicone rubber, a flexible, colored and conductive graphene/SR can be obtained.

Abstract: We develop a simple and competitive fabrication of antireflective (AR) films with high-ordered nanostructure arrays on polycarbonate (PC) substrate by using gas-assisted hot embossing and a self-assembled technique. In this method, a self-assembled monolayer of polystyrene (PS) nanospheres is well-patterned on glass substrates as the first template. Subsequently, we use the plasma sputtering to deposit a conductive layer onto the surface of nanosphere (NS) patterned substrates, and then, electroforming is applied to fabricate a nickel mold with an inverse shape of nanospheres. In the last step, a unique glass transition is utilized to duplicate nanostructures on PC films via gas-assisted hot embossing. Not only in visible light but in near infrared, the optical properties of this AR film are similar or better than for other methods. This fabrication process also has great potential in industry, with its simplicity, large-area but low-cost.

Abstract: Self-assembled method for controllable fabrication of a hydrophobic triazine dithiol-silane composite film on 304 stainless steel (SS) is reported in this paper. Hierarchical structure composed of micro/nanofeatherlike surface was obtained by acid etching. After modification with 2-( Dibutylamino )-4,6-dimercapto-1,3,5-triazine ( DB ) and n-octadecyltrichlorosilane ( OTS ), the suface became hydrophobicity. By applying SEM, FTIR-RAS, and water contact angle analysis, the surface morphology and hydrophobicity of the as-prepared surfaces were studied in detailed. The results indicated that at the optimal condition, the surface showed a good hydrophobicity with a water contact angle as high as 152±3°. Possible growth mechanism of featherlike hierarchical structure was discussed. Additionally, the anticorrosion effect of the hydrophobic surface was studied by potentiodynamic polarization measurement. It showed that the surface covered with hydrophobic composite film was found to be more positive than bare and monolayer, the corrosion current was significantly lower to 1.68 nA/cm², and the corrosion potential shifted positively from-253 mV to-118 mV ( vs SEC ).

Abstract: To make fuels and oxides react better, Iron oxide nanoring was synthesized using hydrothermal method and then self-assembled with nano aluminum particles. Iron oxide were characterized by hollow column morphology with outer diameters of 200-240nm, inner diameters of 90-120nm and heights of 120-150nm using SEM and TEM. Iron oxide and aluminum were evenly distributed and contact closely by self-assembly.The touch of fuels and oxides increased effectively.While the ultrasonically-mixed sample scattered randomly and aggregated seriously. Self-assembly is proved to be a effective method for the touch and distribution of oxides and fuels.

Abstract: In this work, the interaction between paclitaxel (PTX) and a designed peptide was investigated through AFM, CD and fluorescence spectroscopy. AFM images showed that the morphology of the self-assembling peptide with PTX addition had a remarkable change. Fluorescence data illustrated that PTX enhanced the fluorescence intensity of P1. The binding constants for the interaction between PTX and P1 in 25°Cand 35°Cwere 6.38×105 L/mol and 2.27×104 L/mol respectively. Moreover, thermodynamic analysis implied the main binding force between P1 and PTX was hydrogen bonds and vander Waals forces. CD results indicated that PTX caused an increase of unordered structure. Finally, a molecular modeling was proposed based on the research. The study will provide a reliable proof for designed peptide as a paclitaxel carrier for further research.

Abstract: Non halogen flame retardant researches have achieved great progress; however, theoretical works are much lagged. Here we show a model of an efficient Flame Retardant Carpet (e-FRC) based on the synergistic flame retardant system of phosphorus and hydroxyl compounds that can give ABS UL 94 V-0 efficiently. This model is further extended to explain the high efficient flame retardancy of phosphonates by proposing a surfactant structured intermediate from pyrolysis. The smart intermediate self-assembles on charred polymer matrix, forming an anisotropy molecular membrane, with one side of hydrocarbon groups and the other of inorganic groups. The organic side adheres onto polymeric char, and inorganic side facing the fire, forms an Oxygen Shielding Screen (OSS). The OSS together with charred layer underneath constitutes an e-FRC. This e-FRC structure can be found in earlier reports. It can explain all present existing efficient flame retardant systems.

Abstract: In order to obtain some noticeable microelectronic materials, one-dimensional gold nanowires with diameters down to 50 nm were prepared by electroless plating and gold nano-particles self-assembling. The forming mechanism of gold nanowires that gold nano-particles come into being gold nanowires by self-assembling on surfaces of carbon nanotubes (CNTs) templates at presence of mercapto groups (-SH) was proved. The carbon nanotubes modified by mercapto groups were prepared by reacting with the mixed acid solution of HNO₃ and H₂SO₄, LiAlH₄, PBr₃, NaHS in turn. The microstructure of gold nanowires was shown by TEM image and the active mercapto groups inarched onto surfaces of carbon nanotubes were demonstrated by XPS analysis.

Abstract: This paper explains how to make ferrimagnetic ferrofluid r-Fe₂O₃ with chemical precipitation. First, ferrimagnetic nanoparticle r-Fe₂O₃ is produced with chemical coprecipitation. Then, the ferrofluid r-Fe₂O₃ is synthesized by Massart method. Without magnetic field, the interaction energy of two r-Fe₂O₃particles is about 1.92×10-19J, which is more than heat energy and is easy to form a reunion. There exist ring-like structure in ferrofluidr-Fe₂O₃, which has no contribution to the saturation magnetization. The saturation magnetization is less than the theoretical value. The bigger the volume fraction, the more self-assembly ring structure, the less possible it is to crack in the process of dilution and magnetization.

Abstract: Sm₂S₃ thin films were prepared on Si (100) substrates by liquid phase self–assemble method. The influences of solution pH value on the phases, surface morphologies and optical properties of the as deposited films were investigated. The as–deposited Sm₂S₃ thin films were characterized by X–ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet-visible (UV–Vis). Results indicate that Sm₂S₃ thin film with oriented growth along (105) direction can be obtained at pH value of 3.0, deposition temperature of 80 °C, following deposition for 24 h. The grain sizes of the Sm₂S₃ first increase and then decrease with increasing pH value. The as–deposited thin films exhibit a dense and crystallinized surface morphology. The film shows good transmittance in visible spectrum and excellent absorbency of ultraviolet light, and the bandgap of the thin films at pH of 3.0 is calculated to be 4.06 eV.

Abstract: Collagen is a kind of protein which can self-assemble into collagen gel in vitro at 37°C in neutral pH. In this work, collagen is extracted from bovine tendon and characterized by amino acid analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). When pH of collagen solution is adjusted to 6.6~6.8 and incubated at 37°C for an hour, collagen molecular can be assembling into gel. As a result, collagen fibers in gel observed form electron microscopic (SEM and TEM) look like natural collagen fiber with cross-grain, which is caused by collage molecular assembly behavior. Then mouse embryonic fibroblasts (3T3 cells) are seeded in the gel. Within a period, state of 3T3 cell living in the 3D gel scaffold is observed. As a result, when collagen solution is mixed with 3T3 cells and incubated in vitro, the gel is formed and provides a three-dimensional space for 3T3 cells proliferation at the same time. This study provides a method to make tissue engineering scaffold with cells in situ and predicts its application in soft tissue defect healing.