Han-Yu Hsueh

Inorganic Gyroid with Exceptionally Low Refractive Index from Block Copolymer Templating

Nanoporous polymers with gyroid nanochannels can be fabricated from the self-assembly of degradable block copolymer, polystyrene-b-poly(l-lactide) (PS-PLLA), followed by the hydrolysis of PLLA blocks. A well-defined nanohybrid material with SiO2 gyroid nanostructure in a PS matrix can be obtained using the nanoporous PS as a template for sol-gel reaction. After subsequent UV degradation of the PS matrix, a highly porous inorganic gyroid network remains, yielding a single-component material with an exceptionally low refractive index (as low as 1.1).

Nanoporous Gyroid Nickel from Block Copolymer Templates via Electroless Plating

H.-Y. Hsueh , Prof. R.-M. Ho Department of Chemical EngineeringNational Tsing Hua UniversityHsinchu 30013, Taiwan E-mail: rmho@mx.nthu.edu.tw .-C. Y Huang , Prof. C.-H. Lai Department of Materials Science and EngineeringNational Tsing Hua UniversityHsinchu 30013, Taiwan Makida , . T Prof. H. Hasegawa Department of Polymer ChemistryGraduate School of EngineeringKyoto UniversityNishikyo-ku, Kyoto, 615-8510, Japan

Bicontinuous Ceramics with High Surface Area from Block Copolymer Templates

Mesoporous polymers with gyroid nanochannels can be fabricated from the self-assembly of degradable block copolymer, polystyrene-b-poly(L-lactide) (PS-PLLA), followed by hydrolysis of PLLA block. Well-defined polymer/ceramic nanohybrid materials with inorganic gyroid nanostructures in a PS matrix can be obtained by using the mesoporous PS as a template for sol-gel reaction. Titanium tetraisopropoxide (TTIP) is used as a precursor to give a model system for the fabrication of metal oxide nanostructures from reactive transition metal alkoxides. By controlling the rates of capillary-driven pore filling and sol-gel reaction, the templated synthesis can be well-developed. Also, by taking advantage of calcination, bicontinuous TiO(2) with controlled crystalline phase (i.e., anatase phase) can be fabricated after removal of the PS template and crystallization of TiO(2) by calcination leading to high photocatalytic efficiency. This new approach provides an easy way to fabricate high-surface-area and high-porosity ceramics with self-supporting structure and controlled crystalline phase for practical applications. As a result, a platform technology to fabricate precisely controlled polymer/ceramic nanohybrids and mesoporous ceramic materials can be established.

Well‐Defined Multibranched Gold with Surface Plasmon Resonance in Near‐Infrared Region from Seeding Growth Approach Using Gyroid Block Copolymer Template

Well-defined multibranched gold (Au) in polymers, both as bulk or continuous thin films, can be fabricated by using a nanoporous polymer with gyroid nanochannels as a template. The nanoporous polymer template is obtained from the self-assembly of a degradable block copolymer, polystyrene-b-poly (L-lactide) (PS-PLLA), followed by the hydrolysis of PLLA blocks. Templated seeding growth approach can be conducted to create precisely controlled nanostructured Au giving remarkable surface plasmon resonance (SPR) in (branched Au with uniform distribution in PS matrix) near-infrared (NIR) region. Controlled growth conditions allow the fabrication of three-dimensionally ordered nanoporous Au particles that possess NIR SPR. Double gyroid Au with dual networks in the PS matrix is obtained after completing the seeding growth at which the NIR SPR diminishes resulting from the reduction in the density of nanostructured edge.

Shifting Networks to Achieve Subgroup Symmetry Properties

A simple method for the preparation of nanomaterials with new functionality by physical displacement of a network phase is suggested, giving a change in space group symmetry and hence properties. A double gyroid structure made by the self-assembly of block copolymers is used as a model system for the demonstration of shifting networks to achieve single gyroid-like scattering properties. Free-standing single gyroid-like network materials can be fabricated to give nanophotonic properties, similar to the photonic properties of a butterfly wing structure.

A polymer-based SERS-active substrate with gyroid-structured gold multibranches

Here, we suggest an effective method to create a three-dimensional SERS-active substrate using a nanoporous polymer with bicontinuous nanochannels as a template for electroless plating of gold (Au), resulting in the formation of Au multibranches with sharp tips and corners for high-density and uniformly distributed hotspots as reliable SERS devices for detection. Also, by taking advantage of easy processing of polymeric materials, the polymer-based SERS-active substrate can be effectively fabricated in a large area for device design with mechanical robustness. Crystal violet and β-carotene molecules are used to demonstrate the superior SERS detection sensitivity with high reproducibility and stability using the polymer-based SERS-active substrate, suggesting a new approach to fabricate materials for the detection of chemicals with an average enhancement factor up to 108.

A star polymer with a metallo-phthalocyanine core as a tunable charge storage material for nonvolatile transistor memory devices

We present a strategy for controlling the device performance of organic field effect transistor (OFET) memory devices by using a metallo-phthalocyanine (MPc)-cored star-shaped polystyrene as a charge storage material. MPc-cored four-armed star polymers (M = Cu or Zn) with polystyrene arms of three different number-average molecular weights were prepared by atom transfer radical polymerization and cyclization reactions with metal ions; the density of the MPc cores dispersed in the polymer matrix was dependent on the lengths of polymer arms. The charge carrier mobility of pentacene-based OFET memory devices containing the star polymer varied with the nature of the MPc-cored star polymer layer owing to the presence of the MPc core unit as well as the nanostructures of the polymer thin films. Application of an external gate bias to the OFET device caused significant reversible shifts in the threshold voltage, and the magnitude of the memory shifts was proportional to the weight percentage of MPc cores in the star polymer matrix. The memory device showed a high memory on/off current ratio (>105) and long retention characteristics (>105 s), permitting it to be characterized as a nonvolatile organic memory device; the retention time extended upon increasing the Mn of the star polymer. The MPc-cored star polymer is a promising material designed as a charge storage layer for controlling the performance of organic flash memory devices.

Nanoporous Gyroid-Structured Epoxy from Block Copolymer Templates for High Protein Adsorbability.

Nanoporous epoxy with gyroid texture is fabricated by using a nanoporous polymer with gyroid-forming nanochannels as a template for polymerization of epoxy. The nanoporous polymer template is obtained from the self-assembly of degradable block copolymer, polystyrene-b-poly(l-lactide) (PS-PLLA), followed by hydrolysis of PLLA blocks. Templated polymerization can be conducted under ambient conditions to create well-defined, bicontinuous epoxy networks in a PS matrix. By taking advantage of multistep curing of epoxy, well-ordered robust nanoporous epoxy can be obtained after removal of PS template, giving robust porous materials. The through-hole nanoporous epoxy in the film state can be used as a coated layer to enhance the adsorbability for both lysozyme and bovine serum albumin.