Joo-Hee Kang

One step route to the fabrication of arrays of TiO2 nanobowls via a complementary block copolymer templating and sol–gel process

Highly dense, ordered arrays of a titania (TiO2) nanomaterial with a bowl-shape morphology are generated by using poly(styrene-block-ethylene oxide) (PS-b-PEO) block copolymers as templates combined with a sol-gel process. Porous organic-inorganic hybrid films with titania nanodomains incorporated in the PEO domains can be produced by one step spin-coating. By manipulating the relative composition of the precursor ingredients, a simple protocol to fabricate hexagonally packed arrays of nanobowls is defined. Addition of a second inorganic precursor into the common solution leads to arrays of composite Au-TiO2 nanobowls. Such organic-inorganic hybrids and pure titania nanostructures with controlled shape and size exhibit unique photophysical properties.

Pre-swelled nanostructured electrode for lithium ion battery: TiO2-pillared layered MnO2

Porous structure of layered manganate pillared with titania nanoparticles has been realized by the exfoliation and reassembling route. First, the layered protonic manganese oxide, H0.13MnO2·0.7H2O, is exfoliated by the intercalation of tetrabutylammonium (TBA) ions, and then the exfoliated manganate nanosheets are reassembled in the presence of titania nanoparticles, which results in porous nanohybrid materials. X-Ray diffraction (XRD), cross-sectional transmission electron microscopy (TEM), and Mn K-edge X-ray absorption spectroscopy (XAS) analyses clearly show that the titania nanoparticles with a diameter of 1 nm are successfully intercalated into the two dimensional manganate lattice without any deterioration of electronic structure and local symmetry of Mn ion. According to the N2 adsorption–desorption isotherms, the present nanohybrid is determined to be highly porous with a high specific surface area (106 m2 g−1), which is 10 times larger than that (11 m2 g−1) of the pristine. Finally, electrochemical experiments demonstrate that the specific capacity of the present pillared material is 288 mA h g−1, which is significantly larger than the theoretical value (193 mA h g−1) from the physical mixture of the pristine potassium birnessite and titania nanoparticles.

A Dual-Polymer Electrochromic Device with High Coloration Efficiency and Fast Response Time: Poly(3,4-(1,4-butylene-(2-ene)dioxy)thiophene)–Polyaniline ECD

A new dual-polymer electrochromic device (ECD) composed of poly(3,4-(1,4-butylene-(2-ene)dioxy)thiophene) (PBueDOT) and polyaniline (PANI) with a hydrophobic molten salt electrolyte has been developed. To build this system, an alkylenedioxy ring in the BueDOT backbone was expanded to include a strongly electron-donating alkylenedioxy bridge, and the thickness and surface morphology of the corresponding PBueDOT film were controlled systematically. Not only the dual-electrochromic-polymer-electrode system, but also the expanded alkylenedioxy ring in the BueDOT backbone, synergistically improved the electrochromic performance. From the coloration efficiency (CE) value calculations, we found that the CE was enhanced up to 930 cm(2) C(-1). Furthermore, these ECDs showed an extremely fast response time of less than 80 ms.

Inorganic nanomedicines and their labeling for biological imaging.

In this review, we are going to demonstrate the recent progresses in inorganic nanomaterial-based nanomedicines and their labeling for effective biological imaging. Nanomaterials which are classified according to their dimensionality, from zero- to three-dimensions can be utilized as nanomedicines including drug delivery, therapy and diagnosis. In the following section, the labeling of nanomaterials with various contrasting agents are introduced. Various labeling agents like fluorescence, quantum dots, upconversion nanoparticles, magnetic particles and radioisotopes can be tagged on nanomaterials for effective imaging such as optical, magnetic resonance, computed tomography, positron emission tomography and etc. The labeling of contrasting agent on nanomedicine can be summarized into intercalation, surface modification, embedment and combination depending on how and where the label is tagged. Through these approaches, multimodal biological imaging and multifunctional nanomedicine could be suggested.

Enhanced contrast of electrochromic full cell systems with nanocrystalline PEDOT-prussian blue.

Poly-(3,4-ethylenedioxythiophene) (PEDOT) is an ideal polymer for electrochromic (EC) devices due to its fast response time, high conductivity, and facile fabrication in a doped form except its demerit like an optical contrast limitation. In this study, we developed a simple way to overcome low coloration efficiency of PEDOT through fabricating a complementary PEDOT and prussian blue full cell system. Fundamental properties of EC displays, such as optical contrast, coloration efficiency, and switching speed, could be successfully optimized by controlling the deposition time and applied voltage during EDOT polymerization. In particular, UV transmittance spectra indicated that the optical contrast was enhanced up to 31 approximately 99% at the wavelength of 600 nm. Scanning electron microscopy images showed that the optimized PEDOT and prussian blue films were deposited on ITO glass substrate with an uniform thickness of approximately 180 nm and approximately 190 nm, respectively. Moreover, according to the circuit analysis, the average response time of electric current for the optimized full cell system was about 400 ms. It is, therefore, concluded that such a full cell system could have high potential applications as smart windows and/or optical devices.