Perfluorinated sulfonic acid (PFSA) ionomers have been used as polymer electrolyte membrane (PEM) materials owing to their excellent chemical durability and proton conductivity. However, the PFSA ionomers are suffering from fast hydrogen crossover and, thereby, chemical degradation in the membrane state. To solve these issues is to make reinforced membranes by filling proton-conductive PFSA ionomers in the pores of chemically robust poly(tetrafluoroethylene) (PTFE) support films. However, it is very difficult to obtain PFSA-PTFE reinforced membranes with improved hydrogen barrier property. In this study, PFSA-PTFE reinforced membranes were fabricated by immersing commercial reinforced membrane in PFSA ionomer dispersions with different chemical architectures and particle sizes and their effects were systematically investigated.

Water electrolysis is a representative electrochemical process to generate hydrogen gas together with oxygen gas by applying electric power. Perfluorinated sulfonic acid (PFSA) ionomers have been widely used as electrode binder materials, in addition to polymer electrolyte membrane materials for water electrolysis to generate hydrogen and oxygen gases with a high purity simultaneously. PFSA binder materials act as physical supports for inorganic catalyst materials in both electrodes. The binder materials play role in transporting protons for hydrogen gas and oxygen gas evolution reaction in the cathode and the anode, respectively. In this study, PFSA ionomers with different chemical architectures and equivalent weights were used as binder materials for water electrolysis. The structure property performance relationship was disclosed.

PEMFC is an eco-friendly and sustainable electrochemical generation system to convert chemical energy of fuels into electric energy. Proton exchange membrane(PEM) is key material to decide PEMFC performances. Representative PEM materials is perfluorinated sulfonic acid(PFSA) composed of a chemically stable PTFE backbone and ion conductive side chains. PFSA is classified into long-side chain(LCC-PFSA) and short-side chain(SCC-PFSA). Normally, SCC-PFSA can induce high packing density and gas barrier properties when it is made in PEM state. In spite of these advantages, it is hard to make desirable SCC-PFSA PEMs due to its relatively high Tg and low EW. In this study, the effects of PEM fabrication histories on basic properties of SCC-PFSA ionomers were observed by varying parameters such as casting solvent and thermal annealing condition.

Saline water electrolysis (SWE) is an electrochemical technology to directly generate valued chemicals such as chlorine gas (Cl2), hydrogen (H2), and sodium hydroxide (NaOH) by applying electric energy. The key materials in SWE are cation exchange membranes with high selectivity to sodium ions under chemically harsh SWE conditions. The representative SWE membranes are perfluorinated double layered membranes composed of perfluorinated sulfonic acid layer and carboxylic acid layer to transport sodium ions rapidly and to prevent the passage of hydroxide ions, respectively. The commercially available membranes are, however, suffering from delamination issues occurring in their interface. In this presentation, delamination-free membrane fabrication processes will be addressed.

One of the key components to determine polymer electrolyte membrane fuel cell (PEMFC) performances is a polymer electrolyte membrane (PEM), the representative PEM material is perfluorinated sulfonic acid (PFSA) ionomers. PFSA ionomers such as Nafion®and 3M® ionomers have been widely used as PEM materials for fuel cells owing to their excellent chemical inertness and high proton conductivity. Generally, polymeric materials are highly influenced by the membrane fabrication histories including casting solvents, thermal annealing temperature and time, when they are converted in the membrane forming process. In this study, 3M PFSA ionomer membranes were systematically prepared under different fabrication histories. Their morphological contribution on fundamental characteristics, transport behavior, and electrochemical performances were disclosed.

Chlor-alkali (CA) membrane process is a commercially useful process to produce valued chemicals such as chlorine, sodium hydroxide and hydrogen via salined water electrolysis using sodium ion (Na+)-selective membranes. The most important issue in CA process is to reduce high energy consumption. A plausible solution is to obtain highly Na+-conductive membranes. The representative membrane materials are chemically stable perfluorinated sulfonic acid (PFSA) ionomers such as Nafion® and Aciplex®. PFSA membranes, but it is necessary to develop alternatives to PFSA membranes. In this study, a sulfonated poly(arylene ether sulfone) copolymer membrane is radiation-grafted with a highly sulfonated poly(styrene) used as a side chain material.

The anion exchange membrane (AEM) has a structure having a group of positively charged ions inside, and selectively permeates the anion of the electrolyte. In addition, excellent ion conductivity and chemical durability, and highly reliable electrochemical performance are required. However, commercially available AEMs have a hydrocarbon-based backbone. It is difficult to make the thin film because of low solubility. As a result, it has low ionic conductivity and high area resistivity and shows limitations in electrochemical applications. In this study, a perfluorinated ionomer-based anion exchange membrane with excellent chemical stability is prepared and shows enhanced anion conductivity in electrochemical applications.

Sulfonated poly(arylene ether sulfone) (SPAES) random copolymers have been perceived as alternatives to perfluorinated sulfonic acid (PFSA) ionomers owing to their cheap production cost and low hydrogen permeability. In spite of their advantages, there are some issues to overcome such as membrane durability and relatively low proton conductivity in the low humidity range. An approach to solve these problems is to fill SPAES copolymers into porous support films (e.g., poly(tetra fluoro ethylene), PTFE). However, it is difficult to make defect-free pore-filling membranes. In this study, SPAES nanodispersion in a water-alcohol mixture is made under a modified supercritical condition and used to make highly proton conductive and chemical durable SPAES-PTFE pore-filling membranes.

Saline water electrolysis is a representative electrochemical conversion to produce chlorine gas and sodium hydroxide as major products by applying electric power. Perfluorinated sulfonic acid (PFSA) ionomers have been usually used as polymer electrolyte membrane materials owing to high sodium ion selectivity and strong resistance to acidic compounds (e.g., Cl2, HCl and so on) produced in anode. However, PFSA ionomers have been suffering from chemical degradation occurring when exposed under harsh basic condition in cathode. In this study, double layered chlor-alkali membranes were prepared by anchoring crosslinked hydrocarbon ionomer via radical polymerization technique in water channels located in a surface layer of PFSA ionomer membranes and electrochemically evaluated.

Perfluorinated sulfonic acid (PFSA) ionomers have been widely used as representative polymer electrolyte membrane (PEM) materials for water electrolysis to generate hydrogen and oxygen gases with a high purity (e.g., 99.999%) simultaneously. PEM should satisfy high selectivity of proton to water and act as gas barrier to hydrogen and oxygen in order to improve current efficiency which is a barometer to determine how effectively the electric energy is used for water electrolysis. In this study, PFSA ionomers with different chemical architectures and equivalent weights were used to make PEM materials for water electrolysis. The structure-property-performance relationship was systematically investigated.

This study was investigating the anti-obesity effects of diets with a mixture of cheese, red ginseng and fermented mature fruit of Rubus coreanus Miquel. We fed the experimental diets (SC5, SC10) supplemented with 5% or 10% cheese containing of fermented mixture, then orally administered the extract of fermented mixture (RB100, RB300) at a concentration of 100 or 300 mg/kg body weight to SD rats with high fat diet (HFD). The results were as follows: Sample cheese groups decreased visceral fat mass and adipocyte size of stomach compared to that of HFD group. Additionally, lipid droplets of liver in sample cheese groups were smaller than that in HFD group. The serum triglyceride (TG), total cholesterol (tChol), glucose, leptin, and insulin levels in sample cheese group were lower than that in HFD group. But, the serum adiponectin and HDL-cholesterol (cHDL) levels were higher than that in HFD group. These results suggest that fermentation of red ginseng and Rubus coreanus mixed with cheese might be helpful in preventing obesity in high fat diet-fed rats.

The present experiment was designed to investigate the effects of extruded linseed supplementation on methane production in Holstein steers. Four Holstein steers fitted with permanent cannulas were assigned to two dietary treatments in a duplicated 2 × 2 Latin square design: a control diet consisting of tall fescue straw (65%) and concentrate (35%), and a treatment diet supplemented with 3.8% extruded linseed by replacing a part of ingredients in the concentrate of the control diet. The concentrates of the control and the treatment diet were isoenergetic and isonitrogenous. Extruded linseed supplementation did not affect dry matter intake but significantly (P<0.05) increased the intake of lipid. Rumen pH was significantly (P<0.05) lower for control than for treatment. Although there was no significant difference between treatments, the concentration of total VFA in control was 21% higher than in treatment. The concentrations of acetic acid, propionic acid and butyric acid were not different between treatments. Extruded linseed supplementation significantly (P<0.05) reduced methane output(g/d) and emission factor. Methane conversion rate was lower for treatment than for control but no significant difference was found. The results of the present study showed that extruded linseed supplementation in the diet of Holstein steers could reduce methane output.

This study was conducted with two ruminally cannulated Holstein steers to examine the effect of micronized and steam flaked corn on ruminal fermentation characteristics. The in situ dry matter degradability after 48 h incubation was the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corn treatments. The steam flacked corn (3.3 mm thickness) was degraded lower (P<0.05) than the 2.9 and 3.1 mm thickness of steam flacked corn. Effective dry matter degradability and the rate of constant were the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corns as well. The in vitro dry matter degradability after 48 h incubation was tended to higher (P=0.088) at micronized corn (2.5 mm thickness) than steam flaked corns, whereas there is no significantly difference between steam flaked corn treatments. Total volatile fatty acid concentration was higher at steam flaked corn (2.9 mm thickness) than micronized corn (2.5 mm thickness) and steam flaked corn (3.1 and 3.3 mm thickness). The acetate : propionate ratio was the highest (P=0.008) at steam flaked corn (2.9 mm thickness) and the lowest (P=0.008) at micronized corn (2.5 mm thickness). Total gas and methane production after 48h ruminal incubation was the highest (P=0.001) at micronized corn (2.5 mm thickness) compared with steam flaked corns. According to these results, the thickness of steam flaked corn as resulted corn processing is believed to do not affect methane production. However, further study is needed to better understand the present results to verify the correlation between corn processing method and their thickness on methane production using the same thickness corns by difference processing methods.

Polymer electrolyte membrane (PEM) is one of key elements to determine both electrochemical performances and lifetimes of fuel cell electric vehicles (FCEVs). PEM is exposed to a variety of dynamic stimuli (e.g., temperature, humidity, pressure, fuel gases and so on) under their operation conditions and meets unavoidable mechanical damages derived from unequal pressure difference between anode and cathode feed gases. Even though there have been approaches to evaluate the mechanical strength of PEM materials, most of the trials could provide static information on their mechanical strength. In this study, a pressure-loaded blister hybrid system connected with gas chromatography was developed to disclose the efficacy of the system as an evaluation tool of dynamic PEM strength under realistic FCEV operation conditions.

연료전지용 고분자 전해질막에 있어서 가장 중요한 특성인 수소이온 전달 능력은 내부에서 형성되는 수화채널의 분포 및 형상에 큰 영향을 받게 된다. 비과불화탄소계인 탄화수소계 전해질막의 경우, 과불화탄소계 전해질막인 나피온에 비 하여 이러한 수화채널이 약하게 형성되는 것으로 알려져 있으며 따라서 상대적으로 낮은 이온전달 성능을 나타내는 것으로 보고되고 있다. 본 연구에서는 컴퓨터를 이용한 전산모사 기술의 하나인 메조스케일 전산모사 기술을 이용하여 탄화수소계 연료전지용 전해질막인 술폰화 폴리이미드의 가습조건에서의 수화채널 형성 및 상분리 현상을 관찰하였다. 이를 통하여 술폰 화 폴리이미드 내부에서 물분자 비드는 친수성 영역 전체에 걸쳐서 고르게 분포되며 명확한 수화 클러스터는 높은 술폰화도 에서만 형성되는 것이 관찰되었다. 또한, 술폰화 폴리이미드 모델은 저가습 상태에서 수화 채널을 형성하는데에 나피온 모델 에 비하여 더 어렵다는 것이 관찰되었다. 이러한 결과들은 비과불화불소계인 탄화수소계 전해질막의 수화채널 형성에 대한 기존 이론을 명확하게 뒷받침하고 있으며, 술폰화 폴리이미드의 전도도 경향도 잘 설명을 하고 있다. 따라서 메조스케일 전산 모사 기술은 연료전지용 전해질막의 상분리 현상 및 수화채널을 분석하고 이온전도 특성을 규명하는 데에 있어서 매우 효과 적인 기술이 될 수 있다는 것을 확인하였다.

In vivo assay of glucose detection was described using a skin tattoo film electrode (STF), and the probe was made from carbon nano tube paste modification film paper. Here in the square-wave stripping anodic working range obtained of 20-100 mgL-1 within an accumulation time of 0 seconds only in sea water electrolyte solutions of pH 7.0. The relative standard deviations of 50 mg glucose that were observed of 0.14 % (n=12), respectively, using optimum stripping accumulation of 30 sec, the low detection limit (S/N) was pegged at 15.8 mg/L. The developed results can be applied to the detect of in vivo skin sensing in real time. Which confirms the results are usable for in vitro or vivo diagnostic clinical analysis.

양이온(Na+) 및 음이온(Cl-)이 각각의 CEM과 AEM을 통해 선택적으로 분리되어 담수로 이동할 때 발생되는 전위 차와 산화/환원(redox couple)형 전해질을 포함하고 있는 전극에서 발생하는 전류를 이용하여 전기 에너지로 전환시키는 에너 지변환장치이다. RED 시스템의 핵심소재 중 하나인 이온교환막은 높은 출력 밀도를 달성하기 위해 1) 낮은 팽윤거동, 2) 적 절한 이온교환능, 3) 높은 이온전도도, 4) 높은 이온선택성을 만족시켜야 한다. 본 논문에서는 이를 만족시키는 소재 및 이온 교환막의 연구동향 및 전망에 대해 설명하였다.

A voltammetric analysis of doxycycline was developed using DNA immobilized onto a carbon nanotube paste electrode (PE). An anodic peak current was indicated at 0.2 V (versus Ag/AgCl) in a 0.1M NH4H2PO4 electrolyte solution. The linear working range of the cyclic and square wave stripping voltammetry was obtained to 1-27 ngL-1 with an accumulation time of 800 s. Final analytical parameters were optimized to be as follows: amplitude, 0.35 V; frequency, 500 Hz; and pH, 5.43. Here detection limit was found to be 0.45 ngL-1, this result can be applied in foods systems and in the biological diagnostics

염수전기분해(saline water electrolysis) 또는 클로로-알칼리 막공정(chlor-alkali membrane process)은 양이온교환 막과 전극으로 구성되는 전해셀에 전기를 가하여, 고순도(> 99%)의 고부가가치 화합물(예 : 염소, 수소, 수산화나트륨)을 직 접 제조하는 화학공정이다. 염수전기분해의 경제성은 동일한 양의 화합물을 생산하기 위해 투여되는 에너지 소비량을 저감 시킴으로 달성될 수 있다. 이러한 이슈는 전해질이나 전극의 고유 저항을 줄이거나, 전해질과 전극 사이의 계면 저항을 감소 시킴으로 달성시킬 수 있다. 본 연구에서는 전자빔 동시조사법을 사용하여, 높은 화학적 안정성을 지닌 탄화수소계 술폰산 이 오노머 막의 표면에 높은 이온선택성을 갖는 고분자를 접목 시키는 시도가 이루어졌다. 이를 통해, 고분자 전해질 막의 이온 전도성을 보완함과 동시에, 전극과의 계면 저항을 감소시켜, 전기화학적 효율 향상이 이루어짐을 관찰하였다.