Improving Nucleation in the Fabrication of High-Quality 3D Macro-Porous Copper Film through The Surface-Modification of A Polystyrene Colloid-Assembled Template

A new approach is developed to the fabrication of high-quality three-dimensional macro-porous copper films. A highly-ordered macroporous copper film is successfully produced on a polystyrene sphere (PS) template that has been modified by sodium dodecyl sulfate (SDS). It is shown that this procedure can change a hydrophobic surface of PS template into a hydrophilic surface. The present study is devoted to the influence of the electrolyte solution transport on the nucleation process. It is demonstrated that the permeability of the electrolyte solution in the nanochannels of the PS template plays an important role in the chemical electrodeposition of high-quality macroporous copper film. The permeability is drastically enhanced in our experiment through the surface modi. cation of the PS templates. The method could be used to homogeneously produce a large number of nucleations on a substrate, which is a key factor for the fabrication of the high-quality macroporous copper film.

Fracture of colloidal single-crystal films fabricated by controlled vertical drying deposition

Controlled vertical drying deposition method was used to make high-quality single crystal close-packed colloidal films formed of different radii polystyrene latex spheres on glass substrates coming from a low concentration water suspension (0.1% volume fraction). Regardless of the spheres radii the film thickness was about 6.3 microns. However, cracks destroyed the crystalline film structure during the colloidal film growth. The effect of particle radius (85-215 nm range) on film cracking was systematically studied using in situ optical fracture monitoring. Primary parallel cracks run along the vertical growth direction, later followed by secondary branched cracks in-between the primary cracks due to residual water evaporation. Quantitative theoretical relationship between the cracks spacing and particles radius was derived and shows good agreement with experimental observations. Normalized cracks spacing is related to a reciprocal ratio of the dimensionless particle radius.

Effect of the nature of annealing solvent on the morphology of diblock copolymer blend thin films

The morphologies and structures for the thin film of blend systems consisting of two asymmetric polystyrene-block-polybutadiene (SB) diblock copolymers induced by annealing in the vapor of different solvents, namely, cyclohexane, benzene, and heptane, which have different selectivity or preferential affinity for a certain block, were investigated by tapping mode atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results revealed that even a slight preferential affinity of good solvent for one block would strongly alter the morphology of the blend thin film.

Dewetting behavior of polystyrene film filled with (C6H5C2H4NH3)(2)PbI4

The dewetting behavior of thin (about 30 nm) polystyrene (PS) films filled with different amount of (C6H5C2H4NH3)(2)PbI4 (PhE-PbI4) on the silicon substrate with a native oxide layer was investigated. For different additive concentrations, PhE-PbI4 showed different spatial distributions in the PS films, which had a strong influence on the film wettability, dewetting dynamics, and mechanism. With 0.5 wt % additive, PhE-PbI4 formed a noncontinuous diffusion layer, which caused a continuous hole nucleation in the film. With about 1 wt % additive, a continuous gradient distribution layer of PhE-PbI4 formed in the film, which inhibited the dewetting.

A topography/chemical composition gradient polystyrene surface: Toward the investigation of the relationship between surface wettability and surface structure and chemical composition

In this paper, we have prepared of a topography/chemical composition gradient polystyrene (PS) surface, i.e., an orthogonal gradient surface, to investigate the relationship between surface wettability and surface structure and chemical composition. The prepared surface shows a one-dimensional gradient in wettability in the x, y, and diagonal directions, including hydrophobic to hydrophilic, superhydrophobic to hydrophobic, superhydrophobic to superhydrophilic gradients, and so forth.

Polymer Crystallization Influenced by Initial Orientation of Cylindrical Diblock Copolymers in Thin Films

The effect of the initial states (disordered perpendicular cylinder structure vs. parallel cylinder structure) on the crystallization of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) thin films during cyclohexane annealing was investigated. The cylindrical domains perpendicular or parallel to the surface were obtained by controlling the film thickness. During solvent annealing, for the film with the perpendicular cylinders, the ordering degree of cylinders was increased.

Effect of interfacial roughness on dewetting behavior of polystyrene/poly(methyl methacrylate) bilayer film

The dewetting behavior of polystyrene (PS) film on poly(methyl methacrylate) (PMMA) sublayer was investigated by changing the short-range roughness of the PMMA sublayer systemically. When the bilayer film was heated to the temperature above both Tgs, the protuberances formed in both layers to reduce the system energy. By tracing the dewetting process of the PS up-layer, the dewetting velocity was found to increase with the roughness of the sublayer.

Ring-shaped morphology in H-shaped block copolymer thin films

The formation of ring-shaped structures in an H-shaped block copolymer [a poly(ethylene glycol) backbone with polystyrene branches, i.e., (PS)(2)PEG(PS)(2)] thin film was investigated when it was annealed in saturated PEG-selective acetonitrile vapor. Our results clearly indicate that ring formation is determined by the initial morphology of the spin-coated film, the solvent vapor selectivity and the environmental temperature of the solvent-annealing process. Only the films with the initial core-shell cylindrical structure in strongly PEG-selective acetonitrile vapor could form the ring-shaped structures.

Microphase-Separated Brushes on Square Platelets in PS-b-PEO Thin Films

In polystyrene-block-poly(ethylene oxide) thin square platelets can be obtained via fast solvent evaporation by controlling the tethering density (0.08 < sigma < 0.11). The tethering density of the brushes is proportional to the thickness of the PEO crystal and increases with increasing initial solution heating temperature (T-i). When T-i < T-m, where T-m is the melting point of PEO, brushes with microphase-separated structures are observed. The formation of microphase-separated brushes depends on two factors: the strong incompatibility between PS and noncrystalline PEO chains (attached to the crystalline PEO) and the weak interaction between PS-PS brushes.

Formation of Two Kinds of Hexagonally Arranged Structures in ABC Triblock Copolymer Thin Films Induced by a Strongly Selective Solvent Vapor

An order-order transition (OOT) in the sequence of a hexagonally arranged core-shell cylinder to a double-hexagonally arranged dot in polystyrene-block-poly(butadiene)-block-poly(2-vinylpyridine) (SBV) triblock copolymer thin films is reported to be induced upon exposure to a solvent vapor that: is strongly selective for the two end blocks. These two kinds of hexagonally arranged structures could form when the film thickness is 44, 3.23, and 223 nm. When the film thickness is decreased to 13 nm, the ordered structure is absent. The sizes of the cylinder structures formed with the same annealing time in films of different thickness are compared to address the effects of film thickness on the phase structure. The mechanism is analyzed from the total surface area of the blocks and the effective interaction parameter in the solvent vapor.

ZnO Nanorods as Scatterers for Random Lasing Emission from Dye Doped Polymer Films

A random lasing emission from 4-(dicy-anomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) doped polystyrene (PS) thin films was realized by the scattering role of ZnO nanorods. The device was fabricated by spin-coating DCJTB doped PS on ZnO nanorods. The ZnO nanorods were grown on indium-tin-oxide (ITO) glass substrate by hydrothermal synthesis method. It can be seen that the device emits a resonance multimode peak at center wavelength of 630 nm with a mode line-width of less than 0.23 nm and exhibits threshold excitation intensity as low as 0.375 mJ pulse(-1) cm(-2). The agreement of the dependence of threshold pumped intensity on the excitation area with the random laser theory indicates that the lasing emission realized here is random laser. Our results demonstrate that the nanostructured ZnO nanorods are promising candidate as alternative sources of coherent light emission to realize organic lasers.

Orientation of Syndiotactic Polystyrene Crystallized in Cylindrical Nanopores

Syndiotactic polystyrene (sPS) nanorods with different diameters have been prepared by using anodic aluminum oxide templates, and the orientation of the sPS crystals in the nanorods has been investigated by FT-IR spectroscopy. It is found that the c axis of the beta' crystals preferentially oriented perpendicular to the axis of the nanorod, and the degree of orientation is lower as the diameter of the nanorod decreases. This unexpected result is attributed to nuclei formed at the surface of the nanopores and their subsequent growth, in addition to the preferential growth compatible with the pore direction by the nuclei formed in the bulk film and in the nanorods.

Electrochemiluminescence sensor based on partial sulfonation of polystyrene with carbon nanotubes

Herein, homogenously partial sulfonation of polystyrene (PSP) was performed. An effective electrochemiluminescence (ECL) sensor based on PSP with carbon nanotube (CNTs) composite film was developed. Cyclic voltammetry and electrochemical impendence spectroscopy were applied to characterize this composite film. The PSP was used as an immobilization matrix to entrap the ECL reagent Ru(bpy)(3)(2+) due to the electrostatic interactions between sulfonic acid groups and Ru(bpy)(3)(2+) cations. The introduction of CNTs into PSP acted not only as a conducting pathway to accelerate the electron transfer but also as a proper matrix to immobilize Ru(bpy)(3)(2+) on the electrode by hydrophobic interaction. Furthermore, the results indicated the ECL intensity produced at this composite film was over 3-fold compared with that of the pure PSP film due to the electrocatalytic activity of the CNTs. Such a sensor was verified by the sensitive determinations of 2-(dibutylamino)ethanol and tripropylamine.

Improvement of amplified spontaneous emission performance by doping tris(8-hydroxyquinoline) aluminum (Alq3) in dye-doped polymer thin films

A well-known red fluorescent dye 4-(dicy-anomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran (DCJTB) was codoped with an electron transport organic molecule tris(8-hydroxyquinohne) aluminum (Alq3) in a host matrix of polystyrene (PS), and the amplified spontaneous emission (ASE) was studied by optically pumping. It was found that the ASE performance was significantly improved by the introduction of Alq3. The Alq3:DCJTB:PS blending thin films showed a low threshold (2.4 mu J/pulse) and a high net gain coefficient (109.95 cm(-1)) compared with the pure DCJTB:PS system (threshold of 15.2 mu J/pulse and gain of 35.94 cm(-1)). The improvement of the ASE performance was considered to be attributable to the effective Foster energy transfer from Alq(3) to DCJTB. Our results demonstrate that the Alq(3):DCJTB could be a promising candidate as gain medium for red organic diode lasers.