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A Hollow Microtubular Triazine- and Benzobisoxazole-Based Covalent Organic Framework Presenting Sponge-Like Shells That Functions as a High-Performance Supercapacitor
(2019-05-02)
El-Mahdy, Ahmed F. M.
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Hung, Ying-Hui
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Mansoure, Tharwat Hassan
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Yu, Hsiao-Hua
;
Chen, Tao
In this paper we report the construction of a hollow microtubular triazine- and benzobisoxazole-based covalent organic framework (COF) presenting a sponge-like shell through a template-free [3+2] condensation of the planar molecules 2,4,6-tris(4-formylphenyl)triazine (TPT-3CHO) and 2,5-diaminohydroquinone dihydrochloride (DAHQ-2HCl). The synthesized COF exhibited extremely high crystallinity, a high surface area (ca. 1855m(2)g(-1)), and ultrahigh thermal stability. Interestingly, a time-dependent study of the formation of the hollow microtubular COF having a sponge-like shell revealed a transformation from initial ribbon-like crystallites into a hollow tubular structure, and confirmed that the hollow nature of the synthesized COF was controlled by inside-out Ostwald ripening, while the non-interaction of the crystallites on the outer surface was responsible for the sponge-like surface of the tubules. This COF exhibited significant supercapacitor performance: a high specific capacitance of 256Fg(-1) at a current density of 0.5Ag(-1), excellent cycling stability (98.8% capacitance retention over 1850cycles), and a high energy density of 43Whkg(-1). Such hollow structural COFs with sponge-like shells appear to have great potential for use as high-performance supercapacitors in energy storage applications.
Supramolecular functionalized polybenzoxazines from azobenzene carboxylic acid/azobenzene pyridine complexes: synthesis, surface properties, and specific interactions
(2015-01-01)
Mohamed, Mohamed Gamal
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Hsiao, Chi-Hui
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Hsu, Kuo-Chih
;
Lu, Fang-Hsien
;
Shih, His-Kang
In this study we synthesized Azo-COOH BZ, a new benzoxazine derivative containing both azobenzene and carboxylic acid units, through the reaction of 4-(4-hydroxphenylazo) benzoic acid (Azo-COOH, itself prepared through a diazonium reaction of 4-aminobenzoic acid with phenol in the presence sodium nitrite and NaOH) with paraformaldehyde and aniline in 1,4-dioxane. Fourier transform infrared (FTIR) spectroscopy and H-1 and C-13 nuclear magnetic resonance spectroscopy confirmed the chemical structure of Azo-COOH BZ. We used differential scanning calorimetry (DSC), thermogravimetric analysis, and FTIR spectroscopy to investigate the curing behavior of this new benzoxazine monomer. DSC revealed that the exothermic peak representing the ring opening polymerization of the benzoxazine unit appeared at low temperature relative to those of typical benzoxazines, indicating the presence of the carboxylic acid and azobenzene units of this monomer catalyzing the benzoxazine ring opening reaction. In addition, blending with various molar ratios of a benzoxazine monomer presenting a pyridyl unit (Azopy BZ) led to strong intermolecular hydrogen bonding between the CO2H group of Azo-COOH BZ and the pyridyl group of Azopy BZ. These supramolecular complex systems also featured significantly lower curing temperatures (down from ca. 200 degrees C of Azo-COOH BZ to 150 degrees C of supramolecular complex), with their products retaining the high water contact angles required for low-surface-energy applications.
Bio-Inspired Supramolecular Chemistry Provides Highly Concentrated Dispersions of Carbon Nanotubes in Polythiophene
(2016-06-01)
Lin, Yen-Ting
;
Singh, Ranjodh
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Kuo, Shiao-Wei
;
Ko, Fu-Hsiang
;
材料科學與工程學系
In this paper we report the first observation, through X-ray diffraction, of noncovalent uracil-uracil (U-U) dimeric 7r-stacking interactions in carbon nanotube (CNT)-based supramolecular assemblies. The directionally oriented morphology determined using atomic force microscopy revealed highly organized behavior through pi-stacking of U moieties in a U-functionalized CNT derivative (CNT-U). We developed a dispersion system to investigate the bio-inspired interactions between an adenine (A)-terminated poly(3-adeninehexyl thiophene) (PAT) and CNT-U. These hybrid CNT-U/PAT materials interacted through pi-stacking and multiple hydrogen bonding between the U moieties of CNT-U and the A moieties of PAT. Most importantly, the U center dot center dot center dot A multiple hydrogen bonding interactions between CNT-U and PAT enhanced the dispersion of CNT-U in a high-polarity solvent (DMSO). The morphology of these hybrids, determined using transmission electron microscopy, featured grape-like PAT bundles wrapped around the CNT-U surface; this tight connection was responsible for the enhanced dispersion of CNT-U in DMSO.
Photo-Crosslinking of Pendent Uracil Units Provides Supramolecular Hole Injection/Transport Conducting Polymers for Highly Efficient Light-Emitting Diodes
(2015-05-01)
Shih, Hsi-Kang
;
Chen, Yi-Han
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Chu, Yu-Lin
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Cheng, Chih-Chia
;
Chang, Feng-Chih
A new process for modifying a polymeric material for use as a hole injection transport layer in organic light-emitting diodes has been studied, which is through 2 + 2 photodimerization of a DNA-mimetic -conjugated poly(triphenylamine-carbazole) presenting pendent uracil groups (PTC-U) under 1 h of UV irradiation. Multilayer florescence OLED (Organic light-emitting diodes) device with the PTC-U-1hr as a hole injection/transport layer (ITO (Indium tin oxide)/HITL (hole-injection/transport layer) (15 nm)/N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) (15 nm)/Tris-(8-hydroxyquinoline)aluminum (Alq(3)) (60 nm)/LiF (1 nm)/Al (100 nm)) is fabricated, a remarkable improvement in performance (Q(max) (external quantum efficiency) = 2.65%, B-max (maximum brightness) = 56,704 cd/m(2), and LE (luminance efficiency)(max) = 8.9 cd/A) relative to the control PTC-U (Q(max) = 2.40%, B-max = 40,490 cd/m(2), and LEmax = 8.0 cd/A). Multilayer phosphorescence OLED device with the PTC-U-1hr as a hole injection/transport layer (ITO/HITL (15 nm)/Ir(ppy)(3):PVK (40 nm)/BCP (10nm)/Alq(3) (40 nm)/LiF (1 nm)/Al (100 nm)) is fabricated by successive spin-coating processes, a remarkable improvement in performance (Q(max) = 9.68%, B-max = 41,466 cd/m(2), and LEmax = 36.6 cd/A) relative to the control PTC-U (Q(max) = 8.35%, B-max = 34,978 cd/m(2), and LEmax = 30.8 cd/A) and the commercial product (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) PEDOT:PSS (Q(max) = 4.29%, B-max = 15,678 cd/m(2), and LEmax = 16.2 cd/A) has been achieved.
A facile cosolvent/chelation method for the preparation of semi-crystalline CuCl2(ethylene glycol)/poly(3-hexylthiophene) complexes displaying specific luminescence properties
(2015-01-01)
Lu, Fang-Hsien
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Mohamed, Mohamed Gamal
;
Liu, Tzeng-Feng
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Chao, Chuen-Guang
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Kuo, Shiao-Wei
Semi-crystalline CuCl2(ethylene glycol)/poly(3-hexylthiophene) complexes (CE-P3HT) with specific textures and self-assembled structures can be fabricated using a facile co-solvent/chelation method. The morphologies and self-assembled structures of these CE-P3HT complexes were dependent on the concentration of CuCl2(ethylene glycol) (CuCl(2)EG) in solution. Transmission electron microscopy (TEM) revealed the CE-P3HT sample comprising EG and numerous CuCl2/P3HT dots (C-P3HT dots) that originated from the P3HT main chains interacting with CuCl2 crystals; the average size of this C-P3HT dots was ca. 20 nm. Prior to formation of the solid state of CE-P3HT structures, the CE-P3HT complex in solution displayed a novel phenomenon: a specific luminescence property with an absorption energy gap of 3.71-4.46 eV. This quantum effect resulted from the chelates formed between the Cu2+ ions and the thioether units of the conjugated P3HT polymer.
Unusual Emission of Polystyrene-Based Alternating Copolymers Incorporating Aminobutyl Maleimide Fluorophore-Containing Polyhedral Oligomeric Silsesquioxane Nanoparticles
(2017-03-01)
Mohamed, Mohamed Gamal
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Jheng, Yu-Ru
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Yeh, Shu-Ling
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Chen, Tao
;
Kuo, Shiao-Wei
In this study, we synthesized an unusual 2-aminobutyl maleimide isobutyl polyhedral oligomeric silsesquioxane (MIPOSS-NHBu) monomer lacking conventional fluorescent groups. We then prepared poly(styrene-alt-2-aminobutyl maleimide isobutyl POSS) [poly(S-alt-MIPOSS-NHBu)] and poly(4-acetoxystyrene-alt-2-aminobutyl maleimide isobutyl POSS) [poly(AS-alt-MIPOSS-NHBu)] copolymers through facile free radical copolymerizations using azobisisobutyronitrile as the initiator and tetrahydrofuran as the solvent. A poly(4-hydroxystyrene-alt-2-aminobutyl maleimide isobutyl POSS) [poly(HS-alt-MIPOSS-NHBu)] copolymer was prepared through acetoxyl hydrazinolysis of poly(AS-alt-MIPOSS-NHBu). We employed H-1, C-13, and Si-29 nuclear magnetic resonance spectroscopy; Fourier transform infrared spectroscopy; differential scanning calorimetry; and photoluminescence spectroscopy to investigate the structures and the thermal and optical properties of the monomers and novel POSS-containing alternating copolymers. Intramolecular hydrogen bonding between the amino and dihydrofuran-2,5-dione group and clustering of the locked C = O groups from the POSS nanoparticles in the MIPOSS-NHBu units restricted the intramolecular motion of the polymer chain, causing it to exhibit strong light emission. As a result, the MIPOSS-NHBu monomer and the poly(AS-alt-MIPOSS-NHBu) copolymer both have potential applicability in the detection of metal ions with good selectivity.
Conducting Ag/oligothiophene complex pastes through a simple quenching/chelation method
(2014-08-14)
Lu, Fang-Hsien
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Chang, Feng-Chih
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Mohamed, Mohamed-Gamal
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Liu, Tzeng-Feng
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Chao, Chuen-Guang
This paper describes a simple and environmentally friendly approach-a facile, one-pot, quenching/ chelation method-for the fabrication of a silver paste in the form of Ag/oligothiophene complex composites. These Ag/oligothiophene complex composites possess excellent conductivities of 1.8 x 10(4) S cm(-1) in the bulk state and 6.08 x 10(2) S cm(-1) in the form of thin films. We have used X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) to characterize the microstructures of these novel Ag/oligothiophene complex composites.
Improved reliability from a plasma-assisted metal-insulator-metal capacitor comprising a high-k HfO2 film on a flexible polyimide substrate
(2010-01-01)
Meen, Jagan Singh
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Chu, Min-Ching
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Kuo, Shiao-Wei
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Chang, Feng-Chih
;
Ko, Fu-Hsiang
We have used a sol-gel spin-coating process to fabricate a new metal-insulator-metal (MIM) capacitor comprising a 10 nm-thick high-k thin dielectric HfO2 film on a flexible polyimide (PI) substrate. The surface morphology of this HfO2 film was investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free film growth had occurred on the film surface. After oxygen (O-2) plasma pretreatment and subsequent annealing at 250 degrees C, the film on the PI substrate exhibited a low leakage current density of 3.64 x 10(-9) A cm(-2) at 5 V and a maximum capacitance density of 10.35 fF mu m(-2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when employing O2 plasma at a relatively low temperature (ca. 250 degrees C), thereby enhancing the electrical performance. We employed X-ray photoelectron spectroscopy (XPS) at both high and low resolution to examine the chemical composition of the film subjected to various treatment conditions. The shift of the XPS peaks towards higher binding energy, revealed that O-2 plasma treatment was the most effective process for the complete oxidation of hafnium atoms at low temperature. A study of the insulator properties indicated the excellent bendability of our MIM capacitor; the flexible PI substrate could be bent up to 10(5) times and folded to near 360 degrees without any deterioration in its electrical performance.
Strong Hydrogen Bonding with Inorganic Pendant Polyhedral Oligomeric Silsesquioxane Nanoparticles Provides High Glass Transition Temperature Poly(methyl methacrylate) Copolymers
(2018-01-01)
Yeh, Shu-Ling
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Zhu, Chao-Yuan
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Kuo, Shiao-Wei
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應用化學系
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Department of Applied Chemistry
We report a series of poly(methyl methacrylate) (PMMA) copolymers containing small amounts of methacrylamide (MAAM) and pendant polyhedral oligomeric silsesquioxane (POSS) methyl acrylate (MAPOSS) segments. The hydrogen bonding interactions of the MAAM monomer units and the inorganic POSS nanoparticle units improved the thermal and mechanical properties of the PMMA copolymers. For example, PMMA copolymerization with 5 wt% PMAAM and 5 wt% PMAPOSS monomers could enhance the glass transition temperature to 142 degrees C, with higher modulus, higher water contact angle, and reasonably high transparency. Such copolymers have potential to replace PMMA homopolymers in optical applications.
Stimuli-responsive supramolecular materials: photo-tunable properties and molecular recognition behavior
(2016)
Huang, Cheng-Wei
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Wu, Pei-Wei
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Su, Wei-Hung
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Zhu, Chao-Yuan
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Kuo, Shiao-Wei
A new homopolymer of polystyrene (PS) presenting pendant diaminopyridine (DAP) moieties has been prepared using controlled free radical polymerization and a CuAAC "click" reaction. Through directional complementary multiple hydrogen bonding, this PVB-DAP polymer underwent complexation with a thymine-functionalized azobenzene (Azo-T). The resulting supramolecular complex exhibited amorphous and chromophoric behavior without microphase separation. This strategy allowed the fabrication of homogeneous stimuli-responsive thin films with photocontrollable behavior through photoinduced trans-cis isomerization. The PVB-DAP/Azo-T supramolecular complex facilitated the dispersion of an azo-dye through noncovalent interactions; the resulting complex was used to fabricate a surface relief grating displaying an interference pattern. The "recordability" and "rewritability" of these supramolecular complexes suggest that they are promising materials for optical applications and therefore advance the pathway for supramolecular development.

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