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- 2019
- fan-in/out devices
- polymer optical waveguide
- the Mosquito method
- space division multiplexing
- Optoelectronic Information Science and Engineering
- Keio University
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Evaluation of replicas manufactured in a 3D-printed nanoimprint unit
摘要： Nanoimprint lithography has become a useful tool to prepare elements containing nanoscale features at quite reasonable cost, especially if the fabrication elements are created in the own laboratory. We have designed and fabricated a whole nanoimprint manufacturing system and analyzed the resulting surfaces using ad hoc packages developed on an open-software AFM image analysis suite. To complete the work, a number of polymers have been thoroughly studied in order to select the best material for this implementation. It turned out that the best alternative was not always the same, but depended on the application. A comparative study of the polymers, which takes into account the values and dispersion of numerous sample parameters, has been carried out. As a large number of samples was prepared, an automatized procedure for characterization of nanoimprint surfaces had to be set up. The procedure includes figures of merit for comparative purposes. Materials without the requirement of a solvent were found to be superior for most nanoimprint applications. A large dispersion of the samples was found.
关键词： oriented gradient,nanoimprint,polymer,replica,photoresist
更新于2025-09-23 15:22:29
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Characterization of a novel silicon-containing hybrid polymer by thermal curing, pyrolysis behavior, and fluorescence analysis
摘要： A novel linear silicon-containing hybrid polymer with C C and Si H linkages, diphenyl-dihydroethynyl-silane (DPHES), had been conveniently synthesized and well characterized. The thermal curing, crosslinked structure and pyrolysis behavior were studied by DSC, Fourier transform infrared (FTIR), and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results suggest the crosslinked structures consist mainly of phenyl and aromatic fused rings, which are formed through cyclotrimerization, addition reaction, and hydrosilylation reaction. The thermal properties indicate that the crosslinked DPHES exhibits excellent thermal stability with the temperature at 5% weight loss are higher than 572 and 509 (cid:1)C under nitrogen and air atmosphere, respectively. The ?uorescence emission spectra show DPHES and its crosslinked product also have moderate ?uorescence properties, emitting purple light, and visible blue light, respectively, which further veri?ed the structure of DPHES. These results suggest that DPHES has the potential to be used as light-emitting materials with excellent thermal properties.
关键词： silicon-containing hybrid polymer,?uorescence property,pyrolysis behavior,thermal curing
更新于2025-09-23 15:22:29
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Thermal Characterization of a PPy/PLA Composite by Photoacoustic Calorimetry and Photopyroelectric Techniques
摘要： Recently, conductive polymers have attracted attention in the field of advanced materials. Conducting polymers include polypyrrole (PPy), which is a material with commercial applications due to its stability and electrical conductivity. As technology demands increasingly flexible devices, PPy was mixed with a biodegradable and flexible polymer, polylactic acid, in order to create a composite possessing of newer properties. As it is a new material, thermal properties of this composite such as thermal diffusivity, thermal effusivity, specific heat capacity, and thermal conductivity have been investigated through the application of photoacoustic calorimetry and photopyroelectric techniques.
关键词： PPy/PLA composite,Photoacoustic calorimetry,Polymer,Photopyroelectric technique
更新于2025-09-23 15:22:29
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Carbon nanotubes assisting interchain charge transport in semiconducting polymer thin films towards much improved charge carrier mobility; 碳纳米管辅助共轭聚合物薄膜链间载流子传输以提高迁移率;
摘要： Conjugated polymers attracted much attention in the past few decades due to their wide applications in various optoelectronic devices and circuits. The charge transport process in conjugated polymers mainly occurs in the intrachain and interchain parts, where the interchain charge transport is generally slower than intrachain transport and may slow down the whole charge transport properties. Aiming at this issue, herein we employ semiconducting single-walled carbon nanotubes (s-SWNTs) as efficient charge-transporting jointing channels between conjugated polymer chains for improving the charge transport performance. Taking the typical conjugated polymer, ploy-N-alkyl-diketopyrrolo-pyrrole-dithienylthieno[3,2-b]thiophene (PDPP-TT) as an example, polymer thin film transistors (PTFTs) based on the optimized blended films of PDPP-TT/s-SWNTs exhibit an obviously increasing device performance compared with the devices based on pure PDPP-TT films, with the hole and electron mobility increased from 2.32 to 12.32 cm2 V?1 s?1 and from 2.02 to 5.77 cm2 V?1 s?1, respectively. This result suggests the importance of forming continuous conducting channels in conjugated polymer thin films, which can also be extended to other polymeric electronic and optoelectronic devices to promote their potential applications in large-area, low-cost and high performance polymeric electronic devices and circuits.
关键词： connected conducting channel,conjugated polymer,s-SWNTs,carrier mobility
更新于2025-09-23 15:22:29
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NIR Emission Nanoparticles Based on FRET Composed of AIE Luminogens and NIR Dyes for Two-photon Fluorescence Imaging
摘要： Near-infrared (NIR) nanoparticles (NPs) based on fluorescence resonance energy transfer (FRET) were prepared by co-encapsulation of a red aggregation-induced emission (AIE) molecule, 2-(4-bromophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl)fumaronitrile (TB), and a commercial NIR fluorescence dye, silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (NIR775) with an amphiphilic polymer poly(styrene-co-maleic anhydride) (PSMA). The surface of the NPs, PSMA@TB/NIR775, was modified with poly(ethylene glycol) (PEG) to increase the in vivo biocompatibility of the NPs. The PSMA@TB/NIR775 NPs showed a strong NIR (780 nm) narrow emission and excellent two-photon absorption property. Moreover, the NPs exhibited good monodispersity, stability, and low cytotoxicity. Under the excitation of a 1040 nm femtosecond (fs) laser, the emission peaks at 680 nm of TB and 780 nm of NIR775 excited by FRET were obtained. We utilized PSMA@TB/NIR775 NPs as fluorescent contrast agents for two-photon excited NIR microscopic imaging, and good NIR imaging effect of mouse brain vasculature was obtained with the imaging depth of about 150 μm. The FRET strategy by co-encapsulating AIE molecule and NIR dye will be helpful in preparing more narrow emission NIR probes for deep-tissue biological imaging.
关键词： Two-photon imaging,FRET,NIR emission,AIE,Amphiphilic polymer
更新于2025-09-23 15:22:29
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Role of polysiloxanes in the synthesis of aligned porous silicon oxycarbide ceramics
摘要： The present work focuses on establishing the role of polysiloxane precursors in the synthesis of aligned porous polymer derived silicon oxycarbide ceramics. The precursors used for the synthesis are, polymethylhydrosiloxane, vinyl terminated polydimethylsiloxane and cyclic tetramethyl-tetravinlycyclotetrasiloxane. Hydrotalcite is used for attaining aligned macroporosity during the crosslinking stage itself. Subsequently, pyrolysis of the sample has been carried out to synthesize the ceramics. The evolution of pore structure in these PDCs during the crosslinking and pyrolysis is co-related to the thermal decomposition behaviour. The pore morphology, structure and the size were analyzed using SEM, X-ray computed tomography and BET. Our studies confirm the presence of bimodal porosity in these PDCs. These PDCs have a specific surface area ranging from 77 - 160 m2/g and a total pore volume ranging from 0.18 - 0.29 cm3/g. These results could be significant for achieving a controlled synthesis process of porous materials suitable for various applications like adsorption, filtering and electrochemical storage.
关键词： Mesoporous,X-Ray computed tomography,Pyrolysis,Polymer derived ceramics,Specific surface area
更新于2025-09-23 15:22:29
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A Zn(II)/anthracene coordination polymer showing highly efficient photocatalytic Cr(VI) reduction in aqueous solution
摘要： Reaction of Zn(OAc)2·2H2O with the visible light responsive organic ligand 9,10-bis(4′-pyridylethynyl)-anthracene (BPEA) gave rise to a Zn(II)/anthracene coordination polymer [Zn(OAc)2(BPEA)]n. Compound 1 has a one-dimensional (1D) chain structure in which the binuclear {Zn2(OAc)2} cores are linked by the BPEA ligands using the pyridyl N atoms to give to the 1D ladder-like network. The as-prepared compound 1 shows broad-range visible light absorption and good water stability, which are highly demandable for its application in the photocatalysis. The photocatalytic property of 1 were investigated by reduction of Cr(VI) to Cr(III) in aqueous solution under visible light, which reveals its high efficiency and stability in this photocatalytic process.
关键词： Anthracene-based ligand,Coordination polymer,Photocatalysis,Cr(VI) reduction
更新于2025-09-23 15:22:29
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Preparation and evaluation of fluorescent poly(p-phenyleneethylene) covalently coated microspheres with reactive sites for bioconjugation
摘要： Fluorescent microspheres with reactive sites for interacting with biomolecules are greatly demanded in flow cytometry based suspension array. Aiming to develop new method for preparing fluorescent microspheres, two poly(p-phenyleneethylene) (PPE) conjugated polymers (CPs) with pedant carboxylic groups were synthesized via Sonogarshira coupling and followed with hydrolysis of ester groups; then the conjugated polymers were immobilized onto monodispersed amino-modified porous poly(glycidylmethacrylate) (APGMA) microspheres via coupling reaction between carboxylic and amino groups to give APGMA-CP fluorescent microspheres. The fluorescent microspheres were found to have good photo- and thermal stability as well as negligible influence from rigorous washing. The emission was uniform all across the inner and surface of the spheres. To evaluate the effectiveness of bioconjugation on the fluorescent microspheres, fluorescein isothiocyanate isomer I (FITC) labeled bovine serum albumin (BSA) (BSA-FITC) was chosen as the representative biomolecule to react with the fluorescent microspheres to give APGMA-CP-BSA-FITC. In the flow cytometry study, fluorescence compensation between the V500 and FITC detectors (receiving signals from fluorophores excited by 405 nm and 488 nm, respectively), to remove the interference between the emission of FITC and CPs, was realized using singly-stained microspheres. Finally, APGMA-CP-BSA-FITC microspheres were found to be double positive for CP and FITC with very high percentage (>95%), suggesting the bioconjugation is very effective. This study provides a facile method for simultaneous introduction of fluorescence and reactive sites onto the microspheres, which is very promising to be used as general strategy for fabricating fluorescence microspheres for application in high-throughput technology.
关键词： Fluorescence,Bioconjugation,Flow Cytometry,Microsphere,Conjugated Polymer
更新于2025-09-23 15:22:29
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Non-destructive defect evaluation of polymer composites via thermographic data analysis: A manifold learning method
摘要： Recently, various thermographic data analysis methods have been utilized in the field of non-destructive evaluation (NDE) to process thermal images and enhance the visibility of defects. However, most of them extract only linear features, leading to cumbersome results. In this work, manifold learning is introduced into the thermographic data analysis field. As a nonlinear dimensionality reduction technique, manifold learning can identify an intrinsically low-dimensional manifold in a high-dimensional data space. Specifically, an isometric feature mapping (ISOMAP) based manifold learning thermography (MLT) method is proposed to analyze the thermographic data, which can effectively distinguish the uneven background, noise, and defect characteristics contained in thermal images and make the defect detection easier. The feasibility of MLT is illustrated using a carbon fiber-reinforced polymer (CFRP) specimen. The results show that, comparing to the conventional linear methods, the present method can better determine the defect information, including the positions, sizes, and shapes.
关键词： Thermographic data analysis,Non-destructive evaluation,Manifold learning,Active infrared thermography,Carbon fiber-reinforced polymer
更新于2025-09-23 15:22:29
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Enzyme immobilization in completely packaged freestanding SU-8 microfluidic channel by electro click chemistry for compact thermal biosensor
摘要： Enzyme immobilization method in packaged freestanding microfluidic channel is developed for biomolecule assembly of biosensor in this research. A new micro fluidic fabrication method is proposed to fabricate freestanding fluidic structure by MEMS technology. The SU-8 polymer channel is treated by plasma treatment to change hydrophobic surface to hydrophilic property which can automatically drive the liquid into the channel by capillary force. The electro click chemistry method is carried out in hydrophilic SU-8 micro channel by capillary effect. The results show that enzyme immobilization can be immobilized by electro click chemistry in completely packaged freestanding channel. The proposed enzyme immobilization method in micro channel is capable of minimizing biosensor device for healthcare application.
关键词： Capillary effect,SU-8 polymer,Electro click chemistry,Enzyme immobilization,Microfluidic
更新于2025-09-23 15:22:29