Photo Oxidative Degradation of Perfluoropolyether Lubricant for Data Storage

강호종,이지혜,천상욱,Frank E. Talke 한국고분자학회 2011 Macromolecular Research Vol.19 No.6

The degradation mechanism of perfluoropolyethers (PFPE) under UV exposure was investigated. Chain scission was found to be in the methylene (fluorine) and the hydroxyl end chain rather than in the methylene oxide and ethylene oxide main chain where the catalytic Lewis acid degradation was started. This suggests that UV light creates low energy electrons, which initiate the formation of radicals resulting in the chain scission of PFPE. Chain scission was accelerated under an air environment by the oxidation through radical propagation in the methylene (fluorine) end. In addition, the effect of UV degradation on the physical properties of Z-DOL was determined. UV exposure caused the dramatic weight loss of Z-DOL even at low temperatures that were far below the evaporation temperature of Z-DOL. On the other hand, the thermal stability of UV degraded Z-DOL was enhanced by increasing the molecular weight due to the chain extension through reactions between the formed radicals.

퍼프로로폴리에테르 유도체의 루이스 산 분해특성

천상욱(Sang Wook Chun),강호종(Ho Jong Kang) 한국고분자학회 2014 폴리머 Vol.38 No.5

컴퓨터 하드디스크 윤활제로 사용되고 있는 perfluoropolyether(PFPE) 유도체의 분해특성을 살펴보았다. 특히, 이들의 각기 다른 말단기가 분해특성에 미치는 영향을 중점적으로 고찰하였다. 분해 촉매로 사용된 알루미나 존재하에서 PFPE 유도체의 분해는 열분해와 함께 알루미나와의 화학반응에 의하여 발현된 알루미늄 플로라이드가 루이스 산으로 작용하여 진행되는 루이스 산 분해가 일어남을 알 수 있었다. 화학적으로 다른 PFPE 유도체의 말단기는루이스 산 분해에 각기 다른 영향을 미치며 이는 말단기들의 전자 donating 능력이 다르기 때문으로 해석할 수 있다. 즉, PFPE 주사슬 내 동일한 반복 단위체를 가지더라도 유도체 말단기의 전자 donating 능력이 강할수록 반복단위체 내의 아세탈기에 전자밀도가 높아지게 되어 루이스 산에 의한 분자 사슬 절단이 억제됨을 확인하였다. The degradation characteristics of perfluoropolyether (PFPE) derivatives currently being used as computer hard disk lubricants have been investigated. Especially, we considered the effects of end group on degradation behavior of PFPE derivatives. It was found that the degradation of PFPE derivatives in the presence of Al2O3 involves two degradationmechanisms such as thermal degradation and Lewis acid disproportionation by AlF3 which was mainly formed by oxide-to-halide reaction between Al2O3 and the degraded PFPE. The end groups were strongly related to Lewis aciddisproportionation of PFPE derivatives, and it is due to the difference of electron donating ability in the each end groups. Even if PFPE derivatives have same repeating unit in the main chain, Lewis acid disproportionation was prohibited by higher electron donating ability by the end group which caused the high electron density at the acetal group in the repeating unit.

Nano-Rheology of Single Unentangled Polymeric Lubricant Films

Guo, Qian,Chung, Pil Seung,Jhon, Myung S.,Choi, Hyoung Jin WILEY-VCH Verlag 2008 Macromolecular theory and simulations Vol.17 No.9

<P>Rheology and tribology become more and more critical issues in order to satisfy the harsh requirements for ultra-small head/media spacing HDDs. In this communication, MD simulations with a bead/spring model were employed to examine the nano-rheological response of nonfunctional and functional PFPEs by analyzing the shear viscosity of nanoscale PFPE films and the relaxation processes as a function of wall interaction/separation and endgroup functionality. Our simulation results indicate that thin PFPE films show more solid-like behavior, especially under high shear rate. The film deformation and shear viscosity change by tuning the film thickness and the endgroup functionality was discussed in conjunction with the relaxation processes.</P><P> <img src='wiley_img/10221344-2008-17-9-MATS200800048-gra001.gif' alt='wiley_img/10221344-2008-17-9-MATS200800048-gra001'> </P>

분리기술,열역학 : Particle Replication In Non-Wetting Templates (PRINT) 방법을 이용한 약물 및 유전자 전달체의 제작

박지영 ( Ji Young Park ),임종성 ( Jomg Sung Lim ),( Stephanie Gratton ),( Maynor Benjamin ),( Joseph Desimone ) 한국화학공학회 2007 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.45 No.5

Nonflammable Perfluoropolyether-based Crosslinked Gel Polymer Electrolytes for Lithium Batteries

홍동기,백지훈,김동균,이진홍,김상완,이종찬 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Perfluoropolyether-based gel polymer electrolytes (FGPE) were prepared using both liquid state PFPE and PFPE crosslinker via simple UV curing process. Ionic conductivity of the PFPE/lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) electrolyte is firstly investigated with various LiTFSI content to find the optimum value. After preparation of FGPE with optimum electrolyte, its characteristics such as Li+ transference numbers, thermal properties, and cell performance are investigated. The ionic conductivity of the FGPE at 60 °C are 1.72 x 10^-5 S cm^-1, and the Li+ transference number is 0.53. Also, the FGPE exhibits high combustion resistance and it is thermally stable up to 175 °C without any weight loss. Therefore, the prepared FGPEs are acceptable for safety-enhanced lithium batteries.

불소계 변성이소시아네이트의 합성과 도막의 특성

김성래(Sung Rae Kim),박지용(Ji Yong Park),이상구(Sang Goo Lee),이종대(Jong Dae Lee) 한국고분자학회 2015 폴리머 Vol.39 No.6

도막의 특성 향상을 위해 PTPE-diol을 도입하여 불소계 변성 폴리우레아를 합성하였다. 합성된 perfluorine diisocyanate(PFDI)는 perfluoropolyether-diol(PFPE-diol) 함량에 따라 중평균 분자량은 2480에서 3170로 증가하는 경향성을 보였다. 1H NMR과 FTIR을 통한 화학구조 분석을 통해 PFDI 내에 C-F 결합을 확인하였고 PFPE-diol 함량의 감소함에 따라 C-F 결합피크의 세기도 감소하는 것을 알 수 있었다. 불소의 함량이 증가함에 따라 PFDI와 경화제를 혼합하여 제작된 도막의 경우 열안정성, 내후성, 내약품성, 내오염성 및 내마모성이 향상되는 결과를 얻었다. 반면, 도막의 부착강도, 경도, 음극박리, 인장강도, 신장률 및 인열강도는 상대적으로 저하되었다. The fluorine-containing modified polyurea was synthesized using PTPE-diol in order to improve the film property. The weight-average molecular weight of the prepared perfluorine diisocyanate (PFDI) was found to increase from 2480 to 3170 with increasing perfluoropolyether-diol (PFPE-diol) content. The C-F bond of PFDI compounds was confirmed by the <SUP>1</SUP>H NMR and FTIR, and the intensity of C-F bond decreased as PFPE-diol content decreased. As a result of increasing fluorine content, the film synthesized from PFDI and hardening agent showed that the characteristics of thermal stability, weather resistance, chemical resistance, stain resistance and abrasion resistance were increased. However, the performances of the adhesion strength of the coating film, the hardness, the cathode separation, the tensile strength, elongation and tear strength were relatively decreased.

컴퓨터 하드디스크 윤활제로 사용되는 Perfluoropolyether의 분해거동

이지혜(Ji Hye Lee),천상욱(Sang Wook Chun),강호종(Ho Jong Kang) 한국고분자학회 2007 폴리머 Vol.31 No.4

Preparation of Thermally Stable and Nonflammable Gel Polymer Electrolytes based on Perfluoropolyether for Lithium Batteries

홍동기,백지훈,김동균,이진홍,김상완,이종찬 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

A gel polymer electrolyte (FGPE) based on perfluoropolyether (PFPE) was prepared using PFPE crosslinker via photo-initiated polymerization. The ionic conductivity and Li ion transference number of the prepared electrolyte are 1.72 x 10^-5 S cm^-1 and 0.53 at 60 ℃. The FGPE has high thermal stability, without any weight loss up to 175 ℃, and nonflammability. Moreover, the FGPE shows an excellent electrochemical stability (up to 5.0 V vs. Li/Li⁺). As a result, the FGPE is expected to be suitable electrolyte for safety-enhanced high-temperature lithium batteries.

Recent research trends in perfluoropolyether for energy device applications: a mini review

Shanmugapriya Sathyanarayanan,Kim Myeong Gon,Im Sejin,Jeong Yujin,Surendran Subramani,박태언,윤영훈,이현정,Kim Tae-Hoon,심욱 한국세라믹학회 2024 한국세라믹학회지 Vol.61 No.1

Fluorinated polymers are a significant class of functional materials in the field of polymer chemistry. Endowed with remarkable properties, such as high chemical and solvent resistance, enhanced electrical properties, high thermal and electrochemical stability, and low surface energy, they find potential applications in various fields such as chemical processing, electrical/electronic industries, automotive/aircraft industries, medical instrumentations, consumer products, and energy storage or conversion devices. Among a wide variety of commercially significant fluorinated polymers, perfluoropolyether (PFPE) plays a substantial role in energy applications because of its super-hydrophobicity, non-crystallinity, non-flammability, low toxicity, and gas-permeability features. This review briefly confers the properties, production, and significant studies of perfluoropolyether as electrolytes in batteries, followed by a detailed discussion on their role as solid electrolyte interphase (SEI) in metal-ion batteries, oxygen selective membrane (OSM) in metal–air batteries, and as a hydrophobic coating for gas diffusion electrodes in fuel cell applications. Besides, other energy-related applications of PFPE that open up the future scopes of perfluoropolyether in the field of energy storage and conversion devices are also presented.

연구 논문 : Perfluoropolyether (PFPE)로 처리된 표면의 생물오손 방지 특성 연구

박수인 ( Soo In Park ),권순일 ( Sun Il Kwon ),이영민 ( Yeong Min Lee ),고원건 ( Won Gun Koh ),하종욱 ( Jong Wook Ha ),이상엽 ( Sang Yup Lee ) 한국공업화학회 2012 공업화학 Vol.23 No.1

해조류 및 따개비 등의 해양 생물에 의한 선박 및 해양 구조물 표면의 생물오손(biofouling)은 선박 운영비를 증가시키고 구조물을 유지, 보수하는데 어려움을 가져왔다. 본 논문에서는 이러한 생물오손 방지 또는 생물오손 제거(foulingrelease)를 향상시키는 방안으로 불소계 화합물인 perfluoropolyether (PFPE)를 이용하여 해양 생물의 표면 점착을 억제하는 방법이 연구되었다. 우선 생물오손을 예측할 수 있는 지표로서 물방울 접촉각이 측정되었다. 아민그룹으로 처리된 친수성 표면이 갖는 46.7°의 물방울 접촉각이 PFPE 처리 후 64.5°로 상승하여 표면의 혐수성이 증가하였다. 이로 인해 초기에 따개비 포자 및 해양 미생물의 점착이 친수성 카르복실 표면과 비교시 약 15% 억제되었다. 또한 표면 코팅시 평탄면이 형성되어 PDMS로 처리된 표면 굴곡이 있는 표면보다 점착된 미생물의 제거가 용이하였다. 이러한 점착 억제 특성은 물리화학적 방법을 통해 측정된 물성들과 비교, 분석되었으며, 표면에 점착된 미생물의 염색을 통한 형광도 측정을 통해 표면 점착도가 정량적으로 분석되었다. PFPE가 갖는 가공의 용이성과 저독성 특성으로 인해 PFPE는 향후 단기간 생물학적 방오염이 필요한 해양 구조물 이외에 단백질 점착 억제가 요구되는 의료용 장비 등에 도 활용될 수 있을 것으로 기대된다. Biofouling by marine organisms such as algae and barnacles causes lots of significant problems in marine systems such as a rise of the maintenance-repair cost for the ship and the marine structures. In this work, a fluoropolymer, perfluoropolyether (PFPE), was applied as an anti-biofouling coating material that prevents the adhesion of marine organisms and facilitates the removal of them. Water contact angles of various surfaces were tested to examine the hydrophobicity of the PFPE-modified surface. The PFPE-modified surface showed the water contact angle of 64.5° which is a remarkable rise from 46.7° of amine-treated surface. When the substrate was treated with PFPE, the adhesion on the of the barnacle and other marine organisms were repressed around 15% by the enhanced hydrophobicity. In addition, the removal the of the adhered marine organisms were better comparing to that of the surface prepared by PDMS. Surfaces of the substrate treated by PFPE were characterized through physical and chemical methods to analyze the biofouling results. Degree of biomolecular adhesion to the substrate was quantified by the measurement the fluorescence intensity of marine organisms dyed with green fluorescence. PFPE is expected to be applicable not only to anti-biofouling systems but also to medical devices where the prevention of protein adhesion is required.