Ionic Liquid-based Gel Polymer Electrolytes For Lithium-ion Batteries

KULKARNI UDDHAV 성균관대학교 일반대학원 2025 국내박사

In the last three decades, lithium-ion batteries (LIBs) have received much attention due to their properties such as light weight, high energy density, high ionic conductivity, and negligible memory effect. LIBs could be a promising candidate for energy storage in the face of green alternatives to fossil fuels. Their commercialized version consists of a graphite anode, liquid electrolyte, a cathode made up of metal oxides and a separator. These liquid electrolytes play a vital role in LIBs and ionic conductivity of 10-2 S cm-1 can be achieved. Traditional liquid electrolytes (LEs) pose safety risks due to their flammability and volatility. Ionic liquids (ILs) offer a safer alternative, boasting inherent properties such as non-flammability, thermal stability, and high electrochemical stability, making them ideal for lithium-ion battery applications. The polymeric form of ILs, poly(ionic liquids) (PILs), is a new class of polymer electrolytes which combine the properties of ILs and polymer. However, differently from conventional solid polymer electrolytes (SPEs), in the case of PILs no additional salt needs to be added to the SPE since the pendant counter-ions are free to move and responsible for the ionic conductivity. PILs offers high thermal and electrochemical stability in addition to mechanical stability. Moreover, PILs with bulky anions like bis(trifluoromethanesulfonyl)imide (TFSI) show self-healing properties benefiting the development of flexible polymer electrolytes for wearable electronics. Despite the beneficial properties, use of PILs as battery electrolyte has been hampered due to their low ionic conductivities at room temperature. To address this issue various strategies have been implemented including co-polymerization, addition of plasticizers (like LE, inorganic nanoparticles, ILs, etc.) which has led to enhanced conductivities and exceptional cycling performance. In the first chapter of this thesis, quantitative analysis of factors affecting the physicochemical behavior of ILs in electrolyte solution has been studied. Since solvents or ILs interact with dissociated ions, it is crucial to understand the factors that influence the solvent-solute relationship. Therefore, the ionic interactions are measured by nuclear magnetic resonance (NMR) spectroscopy and quantitively expressed in terms of donor number (DN). DN of ILs offering valuable insights for developing safer and more efficient electrolytes for lithium-ion batteries (LIBs) with enhanced charge-carrying capacity. In the second chapter, crosslinked network polymer of poly(acrylonitrile-r-vinylidene diazide) with tethered tetrazolium rings (xPAN+) as highly stable and ion-selective gel polymer electrolytes (GPEs) for lithium metal batteries. The cationic rings play a crucial role in facilitating the movement of Li ions by interacting with both anions and solvent molecules, resulting in a remarkable transference number and ionic conductivity. Furthermore, the half-cell exhibited excellent capacity retention. In the third chapter, polymer coated silica nanoparticles-based imine vitrimers (P@SNP-PHT) used as polymer electrolytes (PE). These electrolytes show self-healing ability at room temperature without any external stimuli. Moreover, the introduction of P@SNP in polymer matrix increases both stress and strain values of P@SNP-PHT films. P@SNP-PHT films shows high ionic conductivity and moderate lithium transference number with excellent electrochemical stability. The research investigates the fundamental properties of ionic liquids and their interactions with Li salts, aiming to develop novel ionic-polymer electrolyte systems with enhanced lithium transference numbers and self-healing capabilities.

Catalytic investigations of Chitosan, Ionic Liquids, and Metal Oxide based materials towards the fixation of carbon dioxide into dimethyl carbonate

Tamboli Ashif Hiralal Tamboli Ashif Hiralal 2017 해외박사

Catalytic investigations of Chitosan, Ionic Liquids, and Metal Oxide based materials towards the fixation of carbon dioxide into dimethyl carbonate Tamboli Ashif Hiralal Department of Energy Science and Technology Graduate School, Myongji University Directed by Professor Kim Hern This study gives emphasis to the use of naturally abundant, recyclable and inexpensive materials (carbon dioxide, chitosan, and urea) with simplistic and eco-friendly methods (microwave) in the synthesis of highly active catalysts for dimethyl carbonate production from carbon dioxide and methanol. A wide range of catalyst materials has been synthesized such as polymeric, ionic liquids, polyionic liquids ion-gels, metal oxides and solid solutions with novel structures and properties. Carbon dioxide is the chief offender of greenhouse effect which creates vital environmental crisis including global warming, air pollution, and acid precipitation. At the same time, carbon dioxide is naturally abundant, inexpensive, and recyclable future carbon feedstock. In this regards, development of a novel process for the effective utilization of carbon dioxide from the ecological and economical point of view has been the major challenges to the research community. Inspiring by the fact, we took this opportunity to design and synthesize a novel catalyst materials for single step conversion of carbon dioxide into valuable chemical such as dimethyl carbonate. In the development of sustainable and green chemical processes, dimethyl carbonates play a crucial role because of their nonhazardous and environmentally friendly nature having a broad range of applications as solvents, fuel additives, reactants, etc. Although direct dimethyl carbonate synthesis from carbon dioxide and methanol is green and attractive, it is suffering from low yield and thermodynamic limitations. Therefore, an active catalyst is needed for the activation of carbon dioxide and dehydrating agent to remove water from the reaction medium. To overcome these challenges, three types of catalyst materials have been synthesized including naturally abundant chitosan dissolved ionic liquids and chitosan grafted amine derivatives which are composed of carbon dioxide philic amino and hydroxyl groups. These catalyst systems exhibited excellent catalytic activity with methanol conversion in a range of 16.90 to 23.8% and about 99% dimethyl carbonate selectivity. In the next study, a new class of material i.e. polyionic ionic liquid/ ionic liquid ion-gel has been designed with a very high number of free ionic liquids monomer and carbon dioxide permeability. The ion-gel was synthesized by the polymerization of novel carboxyl functionalized vinyl and methylimidazole based ionic liquids. The resulting ion-gel catalyst showed excellent methanol conversion of up to 21.51% with 99% dimethyl carbonate selectivity at ambient reaction conditions. Additionally, the reaction mechanism was proposed with the help of carbon dioxide-ionic liquids interactions and 13C NMR spectroscopy. The conclusive work was focused on the synthesis of metal oxides and solid solutions of ceria, zirconia, Samaria and ceria-zirconia with various morphologies and high surface area for direct dimethyl carbonate production. The main objective of this work was to evaluate the role of catalyst morphology, surface properties and dehydrating agent on the catalytic activity towards direct dimethyl carbonate synthesis. Experimental results revealed that the spindle-shaped morphology offers both higher surface area and catalyst activity, whereas dehydrating agents played an important role and increased product yield effectively. In short, the present study suggests that the novel catalyst systems possessing either carbon dioxide philic functional groups such as amino, hydroxyl, and carboxyl or high carbon dioxide permeability or novel morphology and dehydrating agent are needed for efficient conversion of carbon dioxide. Furthermore, extensive studies are necessary for the determination of reaction mechanism to scale up the title reaction at the industrial level. We hope that this study will offer a new avenue in areas of catalytic processes. 이산화탄소의 디메틸 카보네이트 고정화용 키토산, 이온성 액체 및 금속산화물 기반 소재의 촉매 연구 탐볼리 아시프 히랄랄 명지대학교 대학원 에너지융합공학과 지도교수: 김 헌 본 연구는, 이산화탄소와 메탄올로부터 디메틸 카보네이트 생산용 고활성 촉매의 합성에서, 자연에 풍부하고 재생가능하며 값싼 소재 (이산화탄소, 키토산, 요소)를 사용하고 단순하며 환경친화적인 방법을 개발하는 데 중점을 둔다. 고분자, 이온성 액체, 고분자 이온성 액체 이온젤, 산화금속, 고체 용액 등 새로운 구조와 물성을 지니는 다양한 범주의 촉매 물질이 합성되었다. 이산화탄소는 지구온난화, 대기오염, 산성비 등을 포함하는 실제적 환경문제에 영향을 주는 온실가스의 주범으로 알려져 있다. 동시에, 이산화탄소는 자연적으로 풍부하고 저렴하며 재생가능한 미래 탄소원이기도 하다. 이러한 관점에서 이산화탄소를 효과적으로 이용할 수 있는 새로운 공정의 개발이 환경 및 경제적인 관점에서 대두되고 있다. 이 사실로부터, 본 연구에서는 이산화탄소를 이용하여 디메틸 카보네이트와 같은 부가가치가 큰 화학제품을 단일공정으로 전환시킬 수 있는 새로운 촉매 물질을 설계하고 합성하는 데 목적을 둔다. 지속가능하며 친환경적인 화학공정에서, 디메틸 카보네이트는 무해하며 친환경적인 특성 때문에 다양한 범주의 용매, 연료 첨가제, 반응물 등의 용도를 가지는 중요한 역할을 담당한다. 이산화탄소와 메탄올로부터 디메틸 카보네이트를 직접 생산하는 방법은 친환경적이고 매력적이지만, 수율이 낮고 열역학적인 제한을 받는다. 그러므로 활성화 촉매는, 이산화탄소의 활성화 및 반응물로부터 물을 제거하기 위한 탈수화 용액이 필요하다. 이러한 도전을 극복하기 위하여 3종류의 촉매 물질이 합성 된다. 자연에 풍부한, 이온성 액체에 용해되는 키토산, 키토산 그래프트 아민 유도체 (친이산화탄소 아미노 및 하이트록실기로 구성). 이들 촉매 시스템은 우수한 메탄올 전환 촉매 활성도 (16.9-23.8%) 및 약 99% 디메틸 카보네이트 선택도를 보인다. 다음 연구에서, 새로운 군의 소재, 즉 고분자 이온성 액체/이온성 액체 이온젤 등이, 매우 높은 수의 자유 이온성 액체 모노머와 이산화탄소 투과도를 가지고 설계된다. 이온젤은 새로운 카르복실 기능화된 비닐 및 메틸이미다졸 기반 이온성 액체들의 고분자화를 통하여 합성된다. 결과로 얻는 이온젤 촉매는 21.51%정도까지의 높은 메탄올 전환율 및 99% 디메틸 카보네이트 선택도를 보여준다. 더욱이, 반응 메커니즘은 이산화탄소-이온성 액체 상호작용 및 13C NMR 분광기로 분석된다. 결론적으로, 세리아, 지르코니아, 사마리아, 세리아-지르코니아의 금속산화물, 고체용액의 합성을 촛점을 맞추며 여기서 다양한 구조 형상 및 고표면적을 구현한다. 본 연구의 주된 목적은 촉매 형상의 역할, 표면 물성, 탈수 용액 등의 직접 디메틸 카보네이트 직접 합성시 촉매 활성에 미치는 영향 등을 조사하는 데 있다. 실험 결과들로서, 스피넬-골격의 형상은 보다 큰 표면적 및 촉매 활성도를 제공한다. 한편 탈수 용액은 효과적으로 수율을 증대시키는 중요한 역할을 담당한다. 본 연구는, 아미노, 하이드록시, 카보닐 등과 같은 친이산화탄소 기능성 그룹 또는 새로운 이산화탄소 투과성 또는 새로운 현상, 탈수 용액 등에 대한 고려가 효과적인 이산화탄소 전환을 보장함을 보여 주었다. 더욱이, 반응 메커니즘의 결정, 대량생산을 위한 검토 등의 추가적인 연구를 동반할 수 있다 키워드: 이산화탄소, 온실가스, 디메틸 카보네이트, 촉매, 이온성 액체, 산화금속, 복합체, 수율, 선택도, 활성도

Enhanced Ionic Conductivity of Functional Poly(ionic liquid)s Prepared via Copper (I)-catalyzed Alkyne-Azide Cycloaddition (CuAAC) for Electrochromic Device

Boton, Lilian Graduate School, Myongji University 2019 국내석사

아자이드-PEOn+1-알킨 클릭 화학의 순차적 합성이, 본 연구에서, 성공적으로 정의되었다. 1,2,3-트리아졸륨 기반의 고분자 (이온성 액체) (PIL's)는 구리 촉매 아자이드-알킨 고리화 첨가반응 (CuAAC)를 통해 합성되었다. 합성된 PIL은, 생산된 아자이드-PEOn+1-알킨으로부터 폴리에틸렌 글리콜 (PEOn+1) 스페이서를 함유한다. 서로 다른 스페이서 길이를 갖는 4-PEOn+1-1,2,3-트리아졸 PIL은, 리튬 비스 (트리 플루오로 메탄) 설폰이미드 염을 사용하여 요오드 메탄과 음이온 교환으로 4원화하여 합성하였다. 고분자 (4-PEO6-1,2,3-트리아졸)은 30 ℃에서 1.2 x 10-4 Scm-1의 이온 전도도를 나타내며 동일한 구조이지만 더 낮은 길이를 갖는 다른 PEO 기반 PIL 중에서 가장 높다. 따라서, 스페이서의 길이 및 구조적 성질은 재료 특성에 영향을 미친다. 이 PIL은 22 %의 광학 대조도를 갖는 전기 변색 장치 (ECD)를, 탈색된 상태에서 착색된 상태로 변하는 데 2.5 초, 환원되는 데는 3.2 초 소요되어, 효과적인 착색-탈색 전환이 용이하다. 합성 된 고분자는 에너지 및 환경 응용을 위한 혁신적인 고분자 전해질로서의 이용이 가능하다. Sequential synthesis of Azide-PEOn+1-Alkyne Click Chemistry compatible was successfully defined in this study. 1,2,3-triazolium-based Poly(ionic liquid)s (PIL’s) were synthesized via Copper-catalyzed azide-alkyne cycloaddition (CuAAC). The synthesized PIL contains Polyethylene glycol (PEOn+1) spacer from Azide-PEOn+1-Alkyne produced. The developed main-chain 4-PEOn+1-1,2,3-triazole PIL having different spacer length undertook quarternization with iodomethane and anion exchange using lithium bis(trifluoromethane)sulfonimide salt to attain PIL’s that have promising ionic properties. Poly (4-PEO6-1,2,3-triazole) exhibits an ionic conductivity of 1.2 x 10-4 S cm-1 at 30 0C which is the highest among other main-chain PEO-based PIL’s with the same structure but the lower length of the molecular spacer. Thus, the length and structural nature of the spacer have an influence on the materials properties. This PIL’s effectively shifts an electrochromic device (ECD) that have an optical contrast of 22% from the bleached state shifting to the coloured state in 2.5s and 3.2s to come back to its bleached state. The synthesized polymers have a high potential to be of use as an innovative polyelectrolyte for energy and environmental application.

이온전도 향상을 위한 1,2,3-triazolium poly(ionic liquid)s 의 겔 고분자 전해질 적용

조소영 단국대학교 2025 국내석사

리튬 이온 배터리의 안정성 확보를 위해 고분자 전해질에 대한 연구가 활발히 진행되고 있으며, 특히 고분자와 이온성 액체의 장점을 갖는 poly(ionic liquid)s (PILs)에 기반한 전해질이 주목받고 있다. 본 연구에서는 poly(ethylene oxide) (PEO) 사슬에 1,2,3-triazolium 기능기를 도입한 PIL을 합성하고, lithium salt를 도입하여 전해질 시료를 제조하였다. PIL의 PEO 사슬 길이를 변화시키며 유리전이온도 (Tg), 열안정성, 이온전도도 특성을 분석하였으며, 그 결과 PEO 사슬이 길수록 Tg가 낮아져 상온에서의 이온전도도가 향상됨을 확인하였다. 특히 1.0k-Triazolium (1.0k-TL) 시료는 유사 분자량의 순수 PEO 전해질보다 높은 상온 전도도를 나타내었으며, 이는 triazolium 그룹의 bulky한 구조와 bis(fluorodulfonyl) imide 음이온의 기여로 crystallization이 억제되었기 때문으로 해석된다. 그러나 합성한 PIL은 액체 상태로 존재하기에 고체 전해질로의 응용에 제약이 있으며, 이를 해결하고자 filler 역할을 하는 mesoporous silica를 첨가하여, gel-type의 전해질을 제조하여였다. 다양한 함량의 PIL을 첨가한 결과, 25 wt%가 도입된 GPT-25 시료에서 가장 높은 전도도와 기계적 안정성을 동시에 확보할 수 있었다. Electrochemical impedance spectroscopy 및 Vogel-Fulcher-Tammann (VFT) 분석을 통해 PIL의 사슬 유연성과 segmental motion이 이온 수송에 미치는 영향을 확인하였으며, 본 연구는 triazolium PIL과 mesoporous silica filler를 활용한 PEO 기반 고분자 전해질 플랫폼으로 활용될 수 있음을 보여준다. In this study, a polymer electrolyte based on poly(ionic liquid)s (PILs) was developed to address the safety challenges associated with lithium ion-batteries. The PILs were synthesized by incorporating 1,2,3-triazolium functional groups into poly(ethylene glycol) (PEO) chains, and lithium salt was added to prepare the electrolyte samples. By varying the length of the PEO chains, the glass transition temperature (Tg), thermal stability, and ionic conductivity were systematically analyzed. The results revealed that longer PEO chains led to lower Tg values and enhanced ionic conductivity at room temperature. Notably, the 1.0k-TL sample exhibited higher conductivity than a pure PEO-based electrolyte of comparable molecular weight, which is attributed to the crystallization suppression effect of the bulky triazolium groups and TFSI- anions. However, the synthesizes PILs existed in a liquid state, limiting its applicability as a solid electrolyte. To overcome this limitation, a gel polymer electrolyte (GPE) was fabricated using mesoporous silica as a filler. Among the various compositions tested, the GPT-25 sample containing 25 wt% 1.0k-TL exhibited the best balance between ionic conductivity and mechanical stability. Electrochemical impedance spectroscopy and Vogel-Fulcher-Tammann (VFT) analysis confirmed the role of polymer chain flexibility and segmental motion in facilitating ion transport. This work demonstrates the potential of triazolium-based PILs combined with mesoporous silica as a next-generation polymer electrolyte platform operable at room temperature.

Electrical double layer capacitor(EDLC) based on poly(ionic liquid)-modified graphene

이현욱 Graduate School, Korea University 2011 국내석사

This thesis report on a high performance electric double layer capaciotor (EDLC) that consists of poly(ionic liquid)-modified reduced graphene oxide (PIL:RG-O) electrode and ionic liquid (IL) electrolyte. The electrode materials based on PIL:RG-O showed an enhanced compatibility with IL electrolyte, because the surface of PIL:RG-O platelets are coated with PIL that have a chemical structure similar to that of IL electrolyte. Though improved compatibility of electrode and electrolyte, a high specific capacitance of ~187 F/g and operating voltages of ~3.5 V have been achieved with this device. Energy density if the device was also measured as high as 6.5 W∙h/kg and these achievement will be discussed in detail.

Development of Stimuli-Responsive Ionic Liquid-Based Materials and their Derivatives Generating Multi-Optical States for Dynamic Control of Solar Light

Padmakar, Mroe Pawan 명지대학교 대학원 2023 국내박사

Smart materials with the ability to alter their color and hence adsorption capability under the influence of stimuli like light (photochromic), temperature (thermochromic) potential bias (electrochromic) is garnering lot of attention due to their diverse applications in the field of smart window, display, and anti-glare car rear-view mirrors. However, despite tremendous progress in this area, there are some major challenges, such as slow response time, poor stability, complex synthesis process etc. Moreover, most chromic material responds to only one stimulus, and often only a single-color change is observed. Thus, significant work is needed to develop new materials that can overcome the abovementioned shortcomings. In this regard, in the present work, we focused on developing chromic material that can produce multiple colors depending upon the magnitude of stimuli provided or can respond to multiple stimuli. The initial work(chapter-3) deals with fabrication of MOFs and 1-hexyl-[4,4′-bipyridin]-1-ium bis (trifluoromethane sulfonyl) imide [MHV][TFSI] based all-in-one hybrid ionogel as an electrochromic device (ECD). The fabricated ECD showed reversible multicolor properties with stability over 2000 cycles. Initially, the ECD showed light yellow color, and subsequently, it changed to light green, blue, and maroon color accordingly. The fabricated ECD displayed fast coloration time(tc), and bleaching times(tb) of 4.35 s and 7.72 s, respectively, along with a coloration efficiency of 99.14 cm2/C. The performance enhancement mechanisms are also concisely discussed in the present thesis. This work introduces a novel way to fabricate MOF-based electrochromic ionogel (ECIG) ECDs and paves the way to the advancement of electrochromic ionogel-based display devices. In further work(chapter-4), it has been revealed that active viologen tethered to poly(2-isopropyl-2-oxazoline) molecule spaced with triazole-bearing oxyethylene chain p-(OEmiPO-HPV) molecules are an excellent single-component dual-band chromic material. p-OEmiPO-HPV, unlike the majority of reported materials of this kind, is not only electrochromic but also thermochromic, exhibiting optical switching as a consequence of a phase transition caused by heat. Each different chromism mode alters visible and NIR light in a unique and independent manner. Multiple color states, including hazy, burgundy, brown, deep purple, and royal blue, are also seen when the spacer length is altered, and the counter anions experience metathesis. The naphthalene diamide divinylimidazol (NDVIm) and pyromellitic dianhydride divinylimidazol (PDVIm) demonstrate photo electrochromic properties which able to absorb visible to NIR spectrum when switched to their colored state. The NDVIm undergoes reduction changing its color from pale yellow to dark brown whereas PDVIm changes from transparent to blue resulting to a maximum optical transmittance of 76% and 51%, respectively. Additionally, NDVIm switches photochromically from pale yellow to dark yellow-green tone. The NDVIm and PDVIm demonstrate a superior capacity of photothermal absorption towards the visible-NIR full range; within 600 s, their temperature reaches up to 68 oC and 52 oC, respectively. Overall, the ILs show good visible-to-NIR absorption ability to modulate solar light. 빛(광변색), 온도(열변색), 전위 바이어스(전기변색)와 같은 자극의 영향 하에서 색상을 변경하고 흡착 능력을 가진 스마트 재료는 스마트 윈도우 분야의 다양한 응용 (디스플레이, 눈부심 방지 자동차 백미러 등)으로 인해 많은 관심을 받고 있다. 그러나 이 분야의 엄청난 발전에도 불구하고 느린 응답 시간, 열악한 안정성, 복잡한 합성 프로세스 등과 같은 몇 가지 주요 과제가 있다. 또한 대부분의 변색 소재는 하나의 자극에만 반응하며 종종 단일 색상 변화에 국한된다. 따라서 위에서 언급한 단점을 극복할 수 있는 새로운 소재를 개발하는 데 다각적인 연구가 필요하다. 이에 본 연구에서는 제공되는 자극의 크기에 따라 다양한 색상을 나타내거나 다중 자극에 반응할 수 있는 변색 소재 개발에 그 연구목적을 두었다. 초기 연구(3장)에서는 MOFs 및 1-hexyl-[4,4'-bipyridin]-1-ium bis (trifluoromethane sulfonyl) imide [MHV][TFSI] 기반의 올인원 하이브리드 아이오노겔 제조에 대해 다룬다. 전기변색소자(ECD)로 제작된 ECD는 2000주기 이상 안정성을 지닌 가역적 다색 특성을 보여주었다. 처음에 ECD는 옅은 노란색을 보였고 이후에 그에 따라 연한 녹색, 파란색 및 적갈색으로 변경되었다. 제작된 ECD는 빠른 발색시간(tc)과 표백시간(tb)이 각각 4.35초와 7.72초, 발색효율은 99.14 cm2/C이었다. 성능 향상 메커니즘도 현재 논문에서 간략하게 제시하였다. MOF 기반 전기변색 이오노겔(ECIG) ECD를 제조하는 새로운 방법을 제시하고 전기변색 이오노겔 기반 디스플레이 장치에도 연계할 수 있는 방향을 제시하였다. 추가 작업(4장)에서 트리아졸 함유 옥시에틸렌 사슬 p-(OEmiPO-HPV) 분자와 간격을 둔 폴리(2-이소프로필-2-옥사졸린) 분자에 연결된 활성 바이올로겐이 우수한 단일 성분이라는 것을 제시하였다. 이중 밴드 크롬 소재로서 p-OEmiPO-HPV는 보고된 대부분의 물질과 달리 전기변색뿐 아니라 열변색도 있어 열로 인한 상전이의 결과로 광 스위칭을 나타낸다. 각기 다른 변색 모드는 고유하고 독립적인 방식으로 가시광선과 근적외선을 영역에서 응답성을 지닌다. 불투명, 진홍색, 갈색, 짙은 보라색, 감청색을 포함한 여러 색상 상태는 스페이서 길이가 변경되고 반대 음이온이 치환 반응에 따라 변화있게 구현할 수 있다. 나프탈렌 디이미드 디비닐이미다졸(NDVIm) 및 파이로멜리트산 이무수물 디비닐이미다졸(PDVIm)은 유색 상태로 전환될 때 NIR 스펙트럼에서 가시광선을 흡수할 수 있는 광전기변색 특성을 나타낸다. NDVIm은 옅은 노란색에서 짙은 갈색으로 변하는 환원 과정을 거치는 반면, PDVIm은 투명에서 파란색으로 변해 최대 광 투과율이 각각 76%와 51%가 된다. 또한 NDVIm은 옅은 노란색에서 짙은 황록색 톤으로 광변색된다. NDVIm 및 PDVIm은 가시광선-근적외선 전체 범위에 대해 우수한 광열 흡수 능력을 보여준다. 600초 이내에 온도는 각각 최대 68 ℃ 및 52 ℃에 도달한다. 전반적으로 IL은 태양광을 변조하는 우수한 가시광선-근적외선 흡수 능력을 보여준다.

Development and application of immobilized lipase assembled with ionic liquid on poly(acrylic acid) beads

여세원 서울대학교 대학원 2014 국내석사

Immobilized enzymes have attracted much attention due to the characteristics of operational stability, enhanced activity, and reusability as well as simple separation. Most of commercial lipases are immobilized form and are used to convert fatty acids to fatty acid alkyl esters (FEs) via an environment-friendly process. Immobilization of enzymes on resin beads has been utilized as a common tool in biological studies as well as bio-industrial field. However, factors controlling the stability of enzyme on resin beads have not been fully explored. So, esterification reactions are designed to evaluate how the stability of Candida antarctica lipase B (CALB) depends on the hydrophilic/hydrophobic properties with or without ionic liquids (ILs) on poly(acrylic acid) (PA) beads, because the ILs can provide a tunable microenvironment to the lipase. The catalytic activities of the immobilized lipases were compared under several factors such as bead properties, immobilization methods, loading levels of ILs, chain lengths of alkyl group on ILs, and solvents. From these results, we found that the IL-grafted PA beads which contained more hydrophilic properties (octyl group) showed better catalytic performance than hydrophobic ones (dodecyl group). The use of tert-butanol as a solvent was a pivotal factor to maintain the activity of the immobilized lipase. Surprisingly, the single type immobilized lipase, PA-C8Im-Lipase, (C8Im loading level, 1.2 mmol/g) showed the best catalytic performance (95% yield) at 50 oC even though the network type immobilized lipase was expected to show the best performance. The single type immobilized lipase can be reused with slightly loss of activity. In conclusion, octyl group provided positive influence to the lipase activity on IL-grafted PA beads without blocking the hydrophobic active site of lipase.

Application of Ionic Liquids and Sulfonated Poly(ether ether)ketone for the Facilitated Olefin Transport

김동범 세종대학교 대학원 2004 국내석사

This research has been peformed to develop the olefin carriers of metal salts-polymer complex, polymer electrolytes, to investigate the coordinative interaction of olefin with silver ions in polymer electrolytes and apply zwitterionic silver complex to the facilitated transport membrane. A remarkable separation performance of isoprene/n-pentane mixtures was observed through facilitated isoprene transport membranes prepared from silver complexes and zwitterionic salts. The performance of zwitterionic-silver complex membranes was tested for the separation of isoprene from n-pentane. The membranes were prepared by casting an aqueous solution containing zwitterionic and silver complex onto a polyester microporous membrane (47 mm, 0.1 ㎛, Whatman) using a doctor blade. Herein, we obtained marvelous phenomenon in the porous membrane. The facilitated membranes based on sulfonated poly(ether ether)ketone (sPEEK) could be used to do the selective diene separation from the isoprene/pentane mixtures. The sPEEK membranes exchanged silver ions showed excellent separation factors for isoprene/pentane mixtures. The sPEEK-AgNO_(3) membrane was prepared and tested for the separation of isoprene/pentane. The membranes showed good selectivity of isoprene over n-pentane and long-term stability.

Ionic liquid impregnated lithium ion conductive solid electrolytes based on poly(acetyl ethylene glycol methacrylate-co-methyl acrylate)

최신우 Sungkyunkwan University 2015 국내석사

Poly(ethylene glycol)methacrylate (PEGMA) was modified with acetyl chloride to afford acetyl-poly(ethylene glycol)methacrylate (AEGMA) containing PEG and carbonyl groups at the pendant position. AEGMA was further reacted with methyl acrylate (MAc) to synthesize poly(AEGMA-co-MAc) copolymer containing additional carbonyl groups. When lithium salts such as lithium perchlorate (LiClO4) and lithium bis(trifluoromethanesulfony)imides (LITFSI) were introduced into the poly(AEGMA-co-MAc) membrane, the ionic conductivity increased with increasing lithium salt concentration up to 15 wt%, followed by a decrease because when the lithium ion concentration was above its saturation level, the excess lithium salts aggregated together exerting a negative effect on ion transport. The maximum ionic conductivity of the copolymer system containing lithium salt was 1.1 × 10-4 S cm-1 at 15 wt% MAc and 15 wt% of LiTFSI concentration. When room temperature ionic liquid (RTIL), PYR14-TFSI in addition to LiTFSI salt was introduced to the poly(AEGMA-co-MAc)-LiTFSI, the ionic conductivity increased monotonically with increasing salt/RTIL concentration. The maximum ionic conductivity of 1.2 × 10-3 S cm-1 was obtained at 70 wt% 0.5 M LiTFSI/PYR14-TFSI concentration.

기상법에 의한 알킬치환 폴리티오펜 박막제조 및 결정화 거동에 관한 연구

송은아 국민대학교 대학원 2009 국내석사

본 연구에서 자기 조립 기상 중합법을 이용하여 이온액체[ILs]가 함유된 Poly(3-Octylthiophene) [P3OT]의 유기반도체 합성을 제조하였다. P3OT는 대표적인 공역계 고분자로서 반도체의 물성을 갖고 있으며, 최근 유기 반도체 및 유기 태양전지 등의 활성층 (Active layer) 으로 많이 이용되고 있다. 그러나 이들의 전하 이동도 가 낮아 이을 향상시키기 위한 공정 및 재료적인 측면에서 많은 연구를 필요로 하고 있다. 자기 조립 기상 중합법으로 합성된 Poly(3-octylthiophene)에 결정성 액체로 알려진 이미다졸계의 이온액체를 첨가하게 됨에 따라 P3OT 분자간의 질서도가 향상되고 π-bonding이 더 조밀하게 되어 결정화도가 크게 증가하는 사실을 알 수 있었다. 또한 이와 관련하여 10~20 cm2/Vs의 높은 carrier mobility를 갖는 유기박막을 제조할 수 있었으며, FE-SEM, AFM, XPS, XRD, Raman 분광 등의 분석을 통한 구조해석과 Hall 소자를 통한 이동도를 관찰하였다. Carrier mobility가 향상되는 이유는 이온액체의 첨가됨에 따라 결정화도, 분자간 질서도의 향상에서 기인된 것으로 설명될 수 있으며, 지금까지 보고된 유기 반도체의 이동도가 많아야 0.1 cm2/Vs 정도임을 고려할 때 10~20 cm2/Vs는 매우 향상된 값이며 이는 높은 전하 이동도를 요구하고 있는 OTFT 및 유기 태양전지 등에 유용하게 이용될 수 있다.