Browsing by Author "Huang, Ching-Mao"

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Electrical bistable memory device based on a poly(styrene-b-4-vinylpyridine) nanostructured diblock copolymer thin film
(2008-11-17)
Huang, Ching-Mao
;
Liu, Yung-Sheng
;
Chen, Chen-Chia
;
Wei, Kung-Hwa
;
Sheu, Jeng-Tzong
This paper describes the performance of a nonvolatile memory device based on a solution-processed poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) diblock copolymer thin film. The Al/PS-b-P4VP/indium tin oxide memory device featuring metal-coordinated 30 nm P4VP cores exhibited an ON/OFF ratio of 2x10(5), an erase voltage of 0.75 V, a write voltage of -0.5 V, and a retention time of 10(4) s. The device exhibited a metallic behavior in the ON state, suggesting the formation of metallic filaments through the migration of Al atoms into the P4VP domain during writing. Such nanostructured diblock copolymer thin films open up avenues for fabricating organic memory devices using simple procedures.
Pseudo-single-crystalline self-assembled structure formed from hydrophilic CdSe and hydrophobic an nanoparticles in the polystyrene and poly(4-vinylpyridine) blocks, respectively, of a polystyrene-b-poly(4-vinylpyridine) diblock copolymer
(2008-10-14)
Huang, Ching-Mao
;
Wei, Kung-Hwa
;
材料科學與工程學系
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Department of Materials Science and Engineering
Self-Assembly of H-Bonded Side-Chain and Cross-Linking Copolymers Containing Diblock-Copolymeric Donors and Single/Double H-Bonded Light-Emitting Acceptors
(2009-09-15)
Lin, Hong-Cheu
;
Jiang, Meng-Dan
;
Wu, Shen-Chang
;
Jou, Leng-Long
;
Chou, Kai-Pin
A series of diblock-copolymers were synthesized through anionic polymerization of styrene and tert-butyl methacrylate (tBuA) with different monomer ratios, and analogous block-copolymeric derivatives (PS-b-PAA)s with monofunctional carboxylic acid groups were obtained by further hydrolyzation as hydrogen-bonded (H-bonded) proton donors. Via H-bonded interaction, these diblock-coplymeric donors (PS-b-PAA)s were incorporated with luminescent mono-pyridyl/bis-pyridyl acceptors to form single/double H-bonded supramolecules, that is, H-bonded side-chain/cross-linking copolymers, respectively. The supramolecular architectures formed by donor polymers and light-emitting acceptors were influenced by the ratio of acid blocks in the diblock copolymeric donors and the type of single/double H-bonded light-emitting acceptors. Their thermal and luminescent properties can be adjusted by H-bonds, and more than 100 nm of red-shifted photoluminescence (PL) emissions were observed, which depend on the degrees of the H-bonding interactions. Self-assembled phenomena of amphiphilic dibolck copolymers and their H-bonded complexes were confirmed by TEM micrographs, and supramolecular microphase separation of spherical micelle-like morphology was demonstrated to affect the photophysical properties. Polymer light-emitting diode (PLED) devices containing H-bonded complexes showed electroluminescence (EL) emissions of 503-560 nm under turn-on voltages of 7.5-9.0 V, maximum power efficiencies of 0.23-0.37 cd/A (at 100 mA/cm(2)), and maximum luminances of 318-519 cd/m(2) (around 25 V). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4685-4702, 2009
Structural evolution of poly(styrene-b-4-vinylpyridine) diblock copolymer/gold nanoparticle mixtures from solution to solid state
(2007-07-10)
Huang, Ching-Mao
;
Wei, Kung-Hwa
;
Jeng, U-Ser
;
Liang, Keng S.
;
材料科學與工程學系
We used in situ annealing small-angle X-ray scattering to monitor the structural evolution of a spherical poly(styrene-b-4-vinylpyridine) diblock copolymer (PS-b-P4VP)/2-phenylethanethiol-coated Au nanoparticle (AuSC2Ph) mixture in the solid state during its thermal annealing. We found that the Au nanoparticles (NPs) that existed initially in a random state with some cluster packing in the PS domain diffused to the interface of the amphiphilic PS-b-P4VP diblock copolymer within 4 h at 170 degrees C under vacuum to form NP-filled shell-like assemblies, as further evidenced from transmission electron microscopy imaging. From the X-ray photoelectron spectroscopy data, we speculate that this interfacial activity of AuSC2Ph results from the fact that the initially hydrophobic Au NP surfaces became increasingly hydrophilic as most of the 2-phenylethanethiol ligands had evaporated off. The Au NP nanoshell assemblies located at the interface between PS and P4VP were quite stable even after redissolving in toluene; they remained in the form of PS-Au-P4VP core/shell/corona onion micelles, as evidenced from solution state small-angle X-ray scattering data.