• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.641-644
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• 2009

We demonstrated a solvent-assisted soft-lithographic patterning method for producing patterned structure and patterned ordering with lyotropic liquid crystalline polymer (LCP) film. Experimental results showed that the liquid crystalline ordering of lyotropic film could be controlled by shearing effects of the fluidic solvent though the patterned mold channels. In this work, two types of lyotropic LCPs were used to investigate the effects of the alkyl chain length of the lyotropic LCP on producing liquid crystalline ordering through the solvent-assisted fluidic patterning.

• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.301-306
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• 2014

A porous silicon microcavity (PSMC) sensor has been made for vapors of solvent solutions, and a method has been developed in order to obtain simultaneous determination of two volatile substances with different concentrations. In our work, the temperature of the solution and the velocity of the air stream flowing through the solution have been used to control the response of the sensor for ethanol and acetone solutions. We study the dependence of the cavity-resonant wavelength shift on solvent concentration, velocity of the airflow and solution temperature. The wavelength shift depends linearly on concentration and increases with solution temperature and velocity of the airflow. The dependence of the wavelength shift on the solution temperature in the measurement contains properties of the temperature dependence of the solvent vapor pressure, which characterizes each solvent. As a result, the dependence of the wavelength shift on the solution temperature discriminates between solutions of ethanol and acetone with different concentrations. This suggests a possibility for the simultaneous determination of the volatile substances and their concentrations.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.96-100
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• 2017

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively studied as the active material in ammonia gas sensor because of its fast response time, high conductivity and environmental stability. It is well known that a post annealing process for organic devices based on PEDOT:PSS significantly increases the device performance. In this study, we propose the solvent annealing of PEDOT:PSS and investigated its effects. As a results, post solvent annealing on PEDOT:PSS lead to the surface chemical and physical properties change. These changes result in improved conductivity of the PEDOT:PSS. In additional, ammonia sensitivity of solvent annealed PEDOT:PSS become higher than pristine polymer film. The enhancement is mainly caused by the depletion of gas barrier PSS and structural re-forming PEDOT networks. We believe that the post solvent annealing is a promising method to achieve highly sensitivity PEDOT:PSS films for applications in efficient, low-cost and flexible ammonia gas sensor.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.47-50
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• 2005

Solvatochromic fluorescence behavior of 8-aminoquinoline based benzothiazole derivative in varying solvent systems has been investigated. Benzothiazole appended 8-aminoquinoline 3 showed distinctive fluorescence color changes depending upon the solvent polarities and the fluorescence color changes occurred over relatively wide span in visible region from 486 nm to 598 nm which can be detected with naked eye. Compound 3 also exhibited significant spectral shifts in ${\lambda}_{em}$ as a function of water composition in binary aqueous solvent systems. The changes are due to the specific interaction of 3 by hydrogen bonding with water as well as general solvent effect. The observed solvatochromic fluorescence characteristics of 3 could be used as a new probe for the micro-environmental polarity changes as well as a sensitive sensor for the determination of water composition in binary aqueous solutions.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.26-29
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• 2005

In this paper, the solvent sensing properties of the metallophthalocyanine macrocyclic compounds(ZnPc) have been deposited as thin films by the spin-coated method and evaporated methods onto alumina substrates and quartz substrates. And then the spin-coated materials of Zinc phthalocyanine solutions blended with $N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,\;1-biphenyl-4,4'-diamine\;and/or\; Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene]$ solutions. The influences of the blended metallophthalocyanine macrocyclic compounds on the resistance have been measured and analysed in five different vapour organic compounds.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2847-2848
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• 2012

• Ceramist
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• v.23 no.1
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• pp.16-26
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• 2020

Recently, polymer-metal composite (IPMC)-based ionic artificial muscle has been drawing a huge attention for its excellent soft actuator performance having outstanding soft actuator performance with efficient conversion of electrical energy to mechanical energy under low working voltage. In addition, light, flexible and soft nature of IPMC and high bending strain response enabled development of versatile sensor application in association with soft actuator. In this paper, current issues of IPMC were discussed including standardizing preparation steps, relaxation under DC bias, inhibiting solvent evaporation, and improving poor output force. Solutions for these drawbacks of IPMC have recently been suggested in recent studies. After following explanation of the IPMC working mechanism, we investigate the main factors that affect the operating performance of the IPMC. Then, we reviewed the optimized IPMC actuator fabrication conditions especially for the preparation process, additive selection for a thicker membrane, water content, solvent substitutes, encapsulation, etc. Lastly, we considered the pros and cons of IPMCs for sensor application in a theoretical and experimental point of view. The strategies discussed in this paper to overcome such deficiencies of IPMCs are highly expected to provide a scope for IPMC utilization in soft robotics application.

• Journal of Sensor Science and Technology
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• v.15 no.5
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• pp.371-377
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• 2006

Nano porous, transparent silica aerogels monoliths were prepared under ambient drying (1 atm, $270^{\circ}C$) condition by the combination of sol-gel process and surface modification with subsequent heat treatment. Three kinds of solvent, n-hexane, n-heptane and xylene, were selected in the point view of low surface tension and vapor pressure in order to restrain a formation of cracks during drying. Crack-free silica aerogels with over 93 % of porosity and below $0.14g/cm^3$ of density were obtained by solvent exchange and surface modification under atmosphere condition. Optimum solvent was confirmed n-heptane among these solvents through estimation of FT-IR, TGA, BET and SEM. Modified silica aerogel exhibited a higher porosity and pore size compare to unmodified aerogels. Hydrophobicity was also controled by C-H and H-OH bonding state in the gel structure and heat treatment over $400^{\circ}C$ effects to the hydrophobicity due to oxidation of C-H radicals.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1581-1586
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• 2006

A La (III) ion-selective membrane sensor has been fabricated from poly vinyl chloride (PVC) matrix membrane, containing 3-hydroxy-N'-(pyridin-2-ylmethylene)-2-naphthohydrazide (HPMN) as a neutral carrier, potassium tetrakis (p-chlorophenyl) borate (KTpClPB) as an anionic excluder and ortho-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The effects of membrane composition and pH as well as the influence of the anionic additive on the response properties were investigated. The sensor with 30% PVC, 62% solvent mediator, 6% ionophore and 2% anionic additive, shows the best potentiometric response characteristics. It displays a Nernstian behavior (19.2 mV per decade) across the range of $1.0{\times}10^{-2}-1.0{\times}10^{-7}$ M. The detection limit of the electrode is $7.0{\times}10^{-8}$ M ($\sim$10 ng/mL) and the response time is 15 s from $1.0{\times}10^{-2}$ up to $1.0{\times}10^{-4} $M and 30 s in the range of $1.0 {\times}10^{-5}-1.0{\times}10^{-7}$ M. The sensor can be used in the pH values of 3.0-9.0 for about seven weeks. The membrane sensor was used as an indicator electrode in the potentiometric titration of lanthanum ions with EDTA. It was successfully applied to the lanthanum determination in some mouth wash preparations.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1153-1159
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• 2013

A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from $3{\times}10^{-7}$ to $1{\times}10^{-2}$ M and a lower detection limit (LDL) of $1{\times}10^{-7}$ M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.