Papers by Keyword: Self-Assembly

Abstract: In this research, a regioregular poly (3-alkylthiophene) derivative had been synthesized via the post-polymerization functionalization, poly (3-hexylamine thiophene), which are soluble in water and water miscible solvents such as methanol, DMSO. The suitable energy level, good thermal stability and water/alcohol solubility of polymers which promising applied in polymer solar cells and processed by water or environmental-friendly solvents. In blend of functionalization polymers and fullerene derivative potassium [6,6]-phenyl-C₆₁-butyrate shows significant UV absorption decay phenomenon and occur precipitates follow with time increase. To further investigate the mechanism of composite, FT-IR analysis and TEM investigate were used, the polymer would be bonded with carboxyl of fullerene derivative via hydrogen bonding in the carboxyl region and TEM images demonstration the mixture that be able to self-assembly a interpenetrating network composite.

Abstract: Well-defined triblock terpolymer polystyrene-block-poly (N,N-Dimethylaminoethyl methacrylate)-block-poly (methyl methacrylate) (PS-PDMAEMA-PMMA) is synthesized via sequential Atom transfer radical polymerization (ATRP) with designed molecular weights characterized by HNMR and GPC. Annealing in Chloroform which is a selective solvent for PS and PMMA induces the formation of micelles with patchy coronas, and subsequent dialysis against cyclohexane which is selective only for PS enables the stacking of the precursor micelles into core-compartmentalized self-assemblies. The micellizatinon and self-assembly behaviors are investigated via DLS and TEM.

Abstract: The ultralong copper nanowires (Cu NWs) with diameter of 90±10 nm and length over 20 μm were synthesized by the self-assembly growth process, in which the copper ions were reduced with hydrazine in an aqueous solution containing NaOH and ethylenediamine (EDA). The prepared Cu NWs were characterized by XRD, SEM and TEM. The results indicate that the ultralong Cu NWs product almost containing no particles can be obtained at 80 °C for 1 h with a proper concentration of EDA. During the growth of Cu NWs, as the EDA moleculars are possibly preferentially absorbed onto the crystal plane of (110), the gowth of Cu NW will be oriented along the crystal plane of (111).

Abstract: A reusable electrochemical biosensing strategy based on gold nanoparticle involved layer-by-layer self-assembly for sensitive detection of single nucleotide polymorphisms is proposed in this study. Making use of the strong sulfur-Au affinity, ethanthiol and capture probe modified gold nanoparticles are self-assembled onto the surface of gold electrode successively. The target DNA hybridizes with the capture probe and ferrocene labeled signaling probe successively via sandwich hybridization reaction. By measuring ac current voltammetry, the target DNA can be sensitively detected in a linear dynamic range from 4.1-410 nM with a low detection limit of 2 nM. Making use of self-assembled gold nanoparticles layer, a large amount of capture probes can be modified onto the gold electrode, supporting the high sensitivity of the proposed strategy. In addition, good reproducibility, high selectivity and stability are achieved. In particular, the biosensor can be easily regenerated by melting in hot water, making it reusable.

Abstract: Freeze-thawed hybridized preparation and the biomimetic self-assembly technique were used to fabricate hydrogel as tissue engineered scaffolds for meniscus tissue. Because of the advantages of both techniques, they were hybridized together as an interesting preparation for hydrogel. Three molecular weights (high, medium, and low) of PVA were prepared in a biomimetic solution before formation into hydrogel by freeze-thawing. The most suitable molecular weight PVA for hydrogel formation was chosen to be mixed with collagen. PVA, PVA/collagen, and collagen were prepared in biomimetic solutions and freeze-thawed into hydrogels. The hydrogels were analyzed and characterized by FTIR, DSC, and SEM. FTIR characterization indicated that high molecular weight PVA formed molecular interaction better than the other molecular weights, and PVA molecules formed molecular interaction with collagen molecules via –OH and C=O groups. DSC characterization showed that the hybridized preparation of freeze-thawing and biomimetic self-assembly kept the characteristics of PVA and collagen. SEM analysis demonstrated that the morphological formation of PVA/collagen was hybridized during freeze-thawing and collagen self-assembly. The morphological structure was organized into a porous network structure. The porous structure showed a rough wall that was formed by the hybridized structure of the crystal domain dispersed in amorphous and collagen self-assembly.

Abstract: Colloidal gold (Au) nanoparticles (NPs) deposition on silicon (Si) substrate is highly affected by the deposition technique and surface properties of the substrate. Spin-coating technique has been proven to be an efficient approach in terms of cost, time and maintaining the quality of the deposition. However, to prevent the agglomeration of NPs and obtain desirable density and distribution of NPs on the substrate, precise control of the spin-coating parameters is required. In this study colloidal Au NPs were spin-coated onto a modified, yet linker-free Si surface. By controlling the spinning speed, acceleration, dwelling time, and the volume of NPs colloidal solution, the density and distribution of the NPs on Si were optimized. Scanning electron microscope was used to investigate the NPs density in each step of the process. Results showed that the distribution of NPs on Si substrate is highly dependent on the spinning speed, duration, and acceleration rate as well as surface properties of Si substrate.

Abstract: This paper presents new effective approachs for the supermolecule film deposition of surface acoustic wave (SAW) chemical sensors for detecting DMMP. 25-(thioalkyl-alkoxy)-p-tertbutylcalix [4] arene self-assembly molecular imprinted film as the sensitive film was coated on the gold delay line of SAW sensors to detect DMMP. The sensor has special response to organoosphorus compounds and the respond characteristic property in different temperatures of SAW sensor was studied in detail, had important reference value in counter-terrorism.

Abstract: Nanoparticles and their ordered arrays have many important applications in fields such as electronic, optical, memory storage devices and sensors. Herein, a simple method was used for fabricating three-dimensional ordered gold nanoparticle arrays with template technique. Gold films were deposited onto anodic aluminum oxide by using electron beam evaporation. After thermal annealing, interestingly, order arrays of gold nanoparticles were obtained by a thermodynamically driven self-assembled process. The spectrum taken by UV-Vis spectrophotometer demonstrates clear surface plasmon resonance at around 500 nm, which appears blue-shift compared with usual gold nanoparticles.

Abstract: Three biodegradable amphiphilic triblock copolymers: polylactide-poly (ethylene glycol)-polylactide (PLA-PEG-PLA), poly (ε-caprolactone)-poly (ethylene glycol)-poly (ε-caprolactone) (PCL-PEG-PCL) and poly (lactide-glycolide)-poly (ethylene glycol)-poly (lactide-glycolide) (PLGA-PEG-PLGA) were synthesized. Their chemical structures were characterized. In aqueous solution, their self-assembly and degradation were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Spherical micelles were formed in aqueous solution via self-assembly of the amphiphilic triblock copolymers. After degradation, the PLA-PEG-PLA and PCL-PEG-PCL micelles became smaller and the PLGA-PEG-PLGA micelles change to vesicles, which should mainly attribute to their different degradation speed.

Abstract: Polyaniline (PANI) nano-thin films were deposited on a novel microstructure silicon (MSS) substrate via in-situ self-assembly approach for NH₃ gas-sensing. The MSS was prepared by alkaline etching process, and gold interdigital electrodes were formed on the MSS surface by vacuum evaporation. The characterization of the MSS and PANI nanothin film were investigated by scanning electron microscope (SEM) and UV-Vis absorption spectroscopy. SEM images showed that the MSS exhibited an orderly uniform hemisphere array structure, and the MSS surface was covered by a compact PANI thin film which consists of PANI nanoparticles and PANI nanofibers. The gas-sensing properties of the sensor were examined at room temperature. The results revealed that the sensor exhibited a good response and recovery characteristics to NH₃.