Polymer surfaces comprising nanopillars with various geometries were prepared by nanoimprinting the surface using anodic aluminium oxide templates. In particular, a simple fabrication method for long-neck vase-like stepped nanopillars was established, and the surface showed considerable enhancement in the water contact angle, for example from 95.7° to 150.6° for the polystyrene surface. This enhanced hydrophobicity could be explained by the desirable reduction in the area of the solid-liquid interface and reduced sticking between the nanopillars.

A major limitation of polyaniline (PANi) electrodes for supercapacitors is the slow rate of ion transport during redox reactions and the resultant easy saturation of areal capacitance with film thickness. In this study, three-dimensionally (3D)-arrayed PANi nanospheres with highly roughened surface nanomorphology were fabricated to overcome this limitation. A hierarchical nanostructure was obtained by polymerizing aniline monomers on a template of 3D-arrayed polystyrene (PS) nanospheres and appropriate oxidative acid doping. The structure provided dramatically increased surface area and porosity that led to the efficient diffusion of ions. Thus, the specific capacitance (C) reached 1570 F g, thereby approaching a theoretical capacitance of PANi. In addition, the retention at a high scan rate of 100 mV s was 77.6% of the C at a scan rate of 10 mV s. Furthermore, 3D-arrayed hollow PANi (H-PANi) nanospheres could be obtained by dissolving the inner PS part of the PS/PANi core/shell nanospheres with tetrahydrofuran. The ruthenium oxide (RuO) nanoparticles (NPs) were also encaged in the H-PANi nanospheres by embedding RuO NPs on the PS nanospheres prior to polymerization of PANi. The combination of the two active electrode materials indicated synergetic effects. The areal capacitance of the RuO-encaged PANi electrode was significantly larger than that of the RuO-free PANi electrode and could be controlled by varying the amount of encaged RuO nanoparticles. The encagement could also solve the problem of detachment of RuO electrodes from the current collector. The effects of the nanostructuring and RuO encagement were also quantitatively analyzed by deconvoluting the total capacitance into the surface capacitive and insertion elements.

Two-dimensionally (2D) arrayed polystyrene (PS)/ruthenium oxide (RuO) core/shell nanospheres are successfully prepared by the electrodeposition of RuO nanoparticles on a hexagonal close-packed PS monolayer. This nanosphere structure is entirely different from the structure previously reported for other transition metal oxides electrodeposited on the PS nanosphere arrays. The different growth behavior is analyzed, and a possible deposition mechanism is proposed based on the morphological evolution and photoelectron spectroscopy measurements. As an electrode for supercapacitors, this 2D arrayed nanosphere structure exhibits superior capacitive properties such as significantly large areal capacitance, tight binding with current collectors, and retarded saturation of the capacitance, compared to a planar RuO film electrode.

Highly transparent energy storage devices have attracted attention owing to their applications in innovative electronics and displays.

Interdependence between stress, preferred orientation, and surface morphology of nanocrystalline TiN thin films deposited by dual ion beam sputtering Growth kinetics, structure, and morphology of para-quaterphenyl thin films on gold (111)