컴퓨터 시스템의 발전과 더불어 과학적 이론의 수식화와 체계화를 통해 고분자 소재의 물성을 예측할 수 있는 다양한 종류의 시스템이 개발되어 왔으며 실제 분자동력학 시뮬레이션을 이용한 고분자 소재의 물성예측은 다양한 분야에 적용되어 왔다. 본 연구에서는 탄화수소계 고분자인 술폰화폴리아릴렌이서술폰 계　고분자와 상용화된 폴리이서술폰, 폴리비닐리덴플로라이드 고분자 소재를 이용한 블렌드 막을 제조하였으며, 제조된 분리막의 함량변화에 따른 이온과 메 탄올 투과물성 변화 예측에 대한 연구를 진행하였으며, 실제 실험결과와 비교분 석을 진행하였다.

본 연구에서는 술폰산기, 암모늄기를 가지는 폴리에테르에테르케톤계 고분자 소재에 대한 투과거동을 분석하기 위하여 분자 동력학 시뮬레이션을 이용하여 분석을 진행하였다. 술폰산기와 암모늄기의 함량을 조절하여 다양한 모델을 구 성하였으며, 도입된 관능기의 함량의 변화에 따른 하이드로니움, 히드록사이드 이온의 투과 거동에 대한 분석을 진행하였으며, 실제 실험 결과와 비교를 진행 하였다.

Synthesis of Li+-selective 14-crown ether (CE) having rigid and bulky subunits was reported. CE-poly(vinyl alcohol) (PVA) dope solutions were electrospun. CEs were immobilized on PVA matrix via acid-catalyzed acetalization using novel aerosol method. Structures of new compounds and their immobilization to PVA were confirmed and characterized. Adsorption experiments show superior lithium capacity and selectivity among previously reported solid-supported CEs. Dihydroxy-dibenzo-14-crown-4 ether-PVA nanofiber membrane showed superior performance. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and future Planning (2015R1A2A1A15055407) and Ministry of Education (2009-0093816).

The anion exchange membrane fuel cells (AEMFCs) have been noticed as the promising power sources. One of the most important components in AEMFC is the anion exchange membranes(AEMs). Recently various materials for AEMs have been investigated for fuel cell applications. Imidazolium-based long alkyl chain multiblock copolymers have drawn much interest due to their well-defined phase separation between hydrophilic and hydrophobic blocks. We report herein the investigation of the effect of block ratio on the phase separation as well as mechanical and electrical properties of the corresponding membranes.

Polyimides (PI) have the high mechanical, thermal, and chemical stability. However, they have low permeability resulting from rigid chain structure. On the other hand, PDMS is a highly CO2 permeable soft polymer. To overcome low permeability of polyimide, we developed PDMS-based polyimide block copolymer. The effect of PDMS contents on the gas separation properties will be discussed in detail.

Graphene oxide (GO) has received a lot of attention in membrane science for its CO2-philic nature, which can facilitate CO2 separation performance. In addition, GO has attractive properties for gas separation membrane material due to thin-film membrane formation and tunable transport channel. GO membrane can be generally prepared by coating GO nanosheets on microporous polymer supports for mechanical stability. However, the substrates for in thin GO layer should be carefully chosen for good adhesion between GO layer and support surface with maintaining good separation performance. In this study, we tried to modify the surface properties of high permeable support membranes by using gutter layer as an intermediate layer, and measured the gas transport properties of these GO thin-film composite membranes.

고분자 분리막은 연료전지, 정수 및 기체분리 등과 같은 여러 과학기술분야에서 핵심 요소로 각광받고 있다. 본 연구에서는 고분자 분리막을 제조와 특성평가를 실시하였다. Zeta potential, 전기영동이동도를 측정하여 전기적특성평가를 진행하였으며, Time lag를 통하여 특정 기체에 대한 분리막의 diffusivity와 solubility를 측정하였다. 분리막의 기공크기에 따른 분리와 이온의 흡착작용 등으로 수투과를 실시하여 water purity를 증가시켰다. 그리고 수분투습도 측정기 (WVTR)와 산소투과도 측정기(OTR)을 이용한 분석과 BET 비표면적 측정기를 이용한 고분자 시료의 비표면적 및 기공 크기분포 분석을 통한 특성평가가 이루어졌다.

Polymer electrolyte membrane fuel cells (PEFCs) are eco-friendly energy conversion systems to convert hydrogen directly into electricity via an electrocatalytic reaction. Representative membrane materials of PEFCs are Perfluorinated sulfonic acid (PFSA) ionomers including Nafion® and 3M ionomers. In spite of high proton conductivity, it is difficult to apply PFSA free-standing membranes in real PEFC applications owing to their weak mechanical failures and thermo-chemical decomposition during PFEC operations, in addition to a relatively high production cost. In this study, Nafion nanodispersions in water-alcohol mixtures are fabricated using a supercritical fluid technique. The fundamental membrane characteristics are compared with those of counterpart membranes obtained from a commercially available Nafion emulsion.

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.

Polymeric materials have been widely used in energy-related applications including fabrication of batteries and fuel cells, pressure retarded osmosis, gas separation and reverse electrodialysis processes. Despite these various versatility, their poor mechanical properties still remain as obstacles for applying to industrial levels. As a way of improving the mechanical properties, Tröger's Base (TB) which is a rigid, V-shaped, and bridged bicyclic amine have been recently introduced. In this work, polyimides incorporating TB units (PI-TBs) were synthesized in-situ polycondensation reaction using dimethoxymethane (DMM). PI-TB membranes were prepared and physicochemical characteristics including mechancial properties were investigated.

Graphene oxide (GO) is an intriguing two-dimensional nanosheet, a highly oxidized graphene sheet. Due to its various oxygen-containing polar functional groups, graphene oxide shows high CO2 sorption properties, and also thin-film GO membranes exhibit good CO2 separation properties, particularly in the presence of water molecules. Recently, GO nanosheets have been incorporated into polymer membranes, in the form of mixed-matrix membranes, to expect the synergistic effect of GO and polymer matrix. Here, we prepared novel GO/polymer membranes via crosslinking reactions between polar groups on basal plane of GO and bi-functional crosslinking agents, and then conducted the gas permeation measurements to see the possible enhancement for permeability/selectivity performance.

Graphene oxide (GO) can be used as a membrane material itself or a nanofiller to enhance gas separation performance of polymer membranes. Since GO has high CO2 affinity due to some polar groups, particularly GO membranes or GO/polymer membranes have been extensively studied for CO2 separation. Although ultrathin GO membranes show outstanding CO2 separation properties, the gas permeance through GO membranes is still low owing to high tortuosity caused by high aspect ratio of GO sheets. In this study, mixed-matrix membranes consisting of modified GO (as a dispersed phase) and high permeable polymer were prepared by combining each advantage of GO and high permeable polymer for improving gas separation performance. Both single-gas and mixed-gas permeation experiments were conducted with or without humidified feeds for post-combustion CO2 capture.

본 연구에서는 소수성 다공성 막의 투과 성능을 향상시키기 위하여 친수성 고분자를 염석법으로 코팅하였다. 코팅된 소수성 막의 코팅유무는 접촉각과 SEM을 이용하여 확인하였다. 막의 내구성을 향상시키기 위하여 Glutaric aldehyde(GA)를 이용하여 코팅용액과 함께 가교하였다. 가장 좋은 친수성 고분자로는 poly(styrere-sulfonic acid-co-maleic acid) (PSSA_MA)이었으며, 이를 이 용하여 코팅하였을 때 투과도 측면에서 80% 향상된 결과를 나타내었다. 또한 가장 좋은 코팅 조건은 코팅용액의 농도 150-300ppm, 이온세기는 0.15, 코팅시 간은 20분으로 도출되었다.

Membrane distillation (MD) has been researched as one of the promising seawater desalination processes, because of its advantages such as (1) high energy efficiency, high water flux and less fouling sensitivity. [1] Herein, thermally rearranged (TR) polymer membranes are introduced for MD application. The TR membranes were investigated by SEM, contact angle, CFP and LEPw. TR membranes showed a great MD performance with high water flux and long-term stability.

Synthetic membranes, based on polymers or inorganic membranes, are now used in a wide variety of gas separations. For gas separation membranes, during the 1980’s, permeability data on six common gases were complied, and the tradeoff relationship was analyzed. The upper bound relationship was established empirically. Recognizing the exquisite permeability and selectivity of biological membranes and the deleterious nature of broad pore size distributions and flexibility of polymer chains on permeability/selectivity combinations, a number of approaches have been pursued to develop membranes with better transport and separation properties. There has been an evolution in design of materials for both gas and liquid separation membranes, brought about by advances in structural control of materials and by better understanding of natural membranes.

Ionomers are polymeric materials containing fixed charged ions (e.g., – SO3 -) to transport their counter ions (e.g., H+, Li+, Na+ and so on) selectively and have been widely used as key components for membrane and unit cell formation targeted for renewable energy generation (e.g., polymer electrolyte membrane fuel cells(PEMFC), redox flow batteries, and reverse electrodialyses) and valued chemical production (e.g., water and brine electrolysis). There are advantages such as high processability, easy solvent evaporation, and chemical inertness, when the ionomers are in the dissolved or dispersed states in water-alcohol mixtures to be applied for these applications. Unfortunately, it is difficult to make homogeneous solution or dispersion using the ionomers with hydrophilic levels undissolved in water. In this study, water-alcohol nanodipsersion with perfluorinated or hydrocarbon sulfonic acid ionomers are fabricated and their feasibilities as PEMFC and electrolysis materials are evaluated.

Novel sulfonated poly(arylene ether sulfone)s multi-block copolymer membranes containing highly sulfonated hydrophilic blocks were synthesized. Different local concentration of sulfonic acid in their hydrophilic blocks affected chemical and physical properties of the SPAES. To investigate the effects of chemical composition on their membrane properties, different hydrophilic oligomers sharing same hydrophobic blocks gave us exact comparison of effect of hydrophilic blocks. The higher concentration of sulfonic acid groups resulted in higher proton conductivity under certain relative humidity conditions than that of the state-of-the-art perfluorinated sulfonic acid membrane and showed that the well-developed phase separation of SPAES.

Sulfonated poly(arylene ether sulfone) copolymers are prepared by an aromatic substitution polymerization reaction as polymer electrolyte membranes for polymer electrolyte membrane fuel cells (PEMFCs). Thin, ductile films are fabricated by the solution casting method, which resulted in membranes with a thickness of approximately 50μm. The synthesized copolymers and membranes are characterized by 1H NMR, FT-IR, TGA, ion exchange capacity, water uptake and proton conductivity measurements. The prepared membranes are tested in a 9 cm2 commercial single cell at 80 ℃ and 120 ℃ in humidified H2/air under different relative humidity conditions. The prepared membrane is found to perform better than the commercial Nafion 112 membrane at 120℃ under low humidity condition.

분리막(Separation membrane)을 이용하여 기체 또는 액체상태로 존재하는 분자들을 선택적으로 분리하는 기술은 화학, 생물, 제약, 석유화학 등의 산업에서 매우 다양하게 응용되고 있으며 산업적으로 매우 큰 비중을 차지하고 있다. Anodic aluminum oxide (AAO) 막은 nanochannel의 직경, nanochannel 간의 거리 및 원통형 nanochannel의 길이 등을 정밀하게 조절 할 수 있어 AAO 막을 이용하여 혼합분자를 효과적으로 분리하려는 다양한 연구가 진행되고 있다. 본 연구에서는 양 말단이 열려있어 through-hole 구조로 다양한 직경의 nanochannel을 가지는 AAO 막을 제작하였으며, 이것을 이용하여 용매에 녹아 있는 고분자 사슬의 수력학적 부피에 따른 선택적 투과를 관찰하였다. Nanochannel을 투과한 고분자 사슬의 회전반지름과 nanochannel의 직경 사이에 정량적인 관계가 있음을 확인하였다. 또한 AAO 막의 nanochannel을 흐르는 고분자 용액의 유동 률(flow rate)이 Hagen-Poiseuille 관계식으로 정확하게 설명될 수 있음을 확인하여 AAO 내에 존재하는 원통형태의 nanochannel 내에서 흐르는 용액의 나노흐름(nanoflow)에 대한 이론적 해석이 가능함을 증명하였다.

본 총설에서는 고분자와 은염으로 구성된 고분자 전해질 분리막과 장시간 안정성을 해결하기 위한 방안들이 정리 되었다. 특히 이온성 액체를 활용하여 AgNO3를 새로운 운반체로 사용하기 위한 방안, 새로운 고분자 매트릭스로서 poly(ethylene phthalate) (PEP)를 활용하는 방안과 가장 최근 알루미늄 염을 활용하여 운반체의 안정성을 부여하는 연구결과들이 정 리되었다. 올레핀 촉진수송을 위한 고분자 나노복합체 분리막의 경우, 운반체인 은 나노입자 표면을 극성화시킬 수 있는 전자 수용체의 종류와 특징들이 소개되었으며, 최근 투과도 성능을 향상시킬 수 있는 연구결과들이 정리되었다.