• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.40-43
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• 2003

최근 관심의 대상이 되고 있는 유기박막트랜지스터 (Organic Thin Film Transisto., OTFT)는 현재 사용되고 있는 무기물 트랜지스터에 비해 가볍고 낮은 공정 온도와 가격으로 인하여 대면적 LCD, EL, smart card의 능동구동소자로서 적용이 가능하다고 알려져 있다[1,2]. 하지만 현재 연구되고 있는 단분자 유기물을 사용한 OTFT는 비교적 높은 온도에서 소자의 각 구성요소를 증착해야 되므로 여전히 복잡한 공정이 필요하며, 활성층으로 쓰이는 유기물과 금속전극의 계면문제로 전기적 특성이 떨어진다[3]. (중략)

• Smart Structures and Systems
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• 제17권5호
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• pp.795-817
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• 2016

A non-contact, in-situ and non-invasive technique for health monitoring of submerged fiber reinforced polymers (FRP) laminates has been developed using ultrasonic guided waves. A pair of mobile transducers at specific angles of incidence to the submerged FRP specimen was used to excite Lamb wave modes. Lamb wave modes were used for comprehensive inspection of various types of manufacturing defects like air gaps and missing epoxy, introduced during manufacturing of FRP using Vacuum Assisted Resin Infusion Molding (VARIM). Further service induced damages like notches and surface defects were also studied and evaluated using guided waves. Quantitative evaluation of transmitted ultrasonic signal in defect ridden FRPs $vis-{\grave{a}}-vis$ healthy signal has been used to relate the extent of damage in FRPs. The developed technique has the potential to develop into a quick, real time health monitoring tool for judging the service worthiness of FRPs.

• Smart Structures and Systems
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• 제4권3호
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• pp.291-304
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• 2008

Piezoelectric materials have been widely used in ultrasonic nondestructive testing (NDT). PZT ceramics can be used to receive and generate surface acoustic waves. It is a common application to attach PZT transducers to the surface of structures for detecting cracks in nondestructive testing. However, not until recently have piezoelectric polymers attracted more and more attention to be the material for interdigitated (IDT) surface and guided-wave transducers. In this paper, an interdigitated gold-on-polyvinylidene fluoride (PVDF) transducer for actuating and sensing Lamb waves has been introduced. A specific etching technology is employed for making the surface electrodes into a certain finger pattern, the spacings of which yield different single mode responses of Lamb waves. Experiments have been performed on steel and carbon fiber composite plates. Results from PVDF IDT sensors have been compared with those from PZT transducers for verification.

• BMB Reports
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• 제43권12호
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• pp.781-788
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• 2010

An often overlooked issue in the field of adenovirus (Ad)-mediated cancer gene therapy is its limited capacity for effective systemic delivery. Although primary tumors can be treated effectively with intralesional injection of conventional Ad vectors, systemic metastasis is difficult to cure. Systemic administration of conventional naked Ads leads to acute accumulation of Ad particles in the liver, induction of neutralizing antibody, short blood circulation half-life, non-specific biodistribution in undesired organs, and low selective accumulation in the target disease site. Versatile strategies involving the modification of viral surfaces with polymers and nanomaterials have been designed for the purpose of maximizing Ad anti-tumor activity and specificity by systemic administration. Integration of viral and non-viral nanomaterials will substantially advance both fields, creating new concepts in gene therapeutics. This review focuses on current advances in the development of smart Ad hybrid nanocomplexes based on various design-based strategies for optimal Ad systemic administration.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.107-107
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• 2013

Many nanomaterials are being harnessed as critical components in various systems for biomedical applications including diagnosis, imaging, and drug delivery. Those systems necessitate biocompatibility and low toxcity within effective dose range while achieving enough efficacy. Even though many nanomaterials enjoy successful demonstrations in bioapplications, lack of biocompatibility and high cytotoxicity often become hurdles for practical bioapplications. On the other hand, it is important to achieve enough efficiency based on chemically well-defined systems with efforts to understand mechanism at molecular level. Here, we developvarious biocompatible nanomaterials based on simple procedure using dextran as both reducing agent and surface coating. Dextran is one of the popular biocompatible polymers that have been used for drug delivery and biosensors. Dextran coated nanomaterials showed excellent colloidal stability, flexible surface chemistry for conjugation of bioactive molecules and low cytotoxicity with successful demonstrations in various bioapplications.

• Smart Structures and Systems
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• 제6권7호
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• pp.867-887
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• 2010

An energy-based variational approach is used for structural dynamic modeling of the IPMC (Ionic Polymer Metal Composites) flapping wing. Dynamic characteristics of the wing are analyzed using numerical simulations. Starting with the initial design, critical parameters which have influence on the performance of the wing are identified through parametric studies. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. It is shown that the optimization algorithm leads to a flapping wing with dimensions similar to the dragonfly Aeshna Multicolor wing. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.

• 전자통신동향분석
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• 제34권4호
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• pp.108-116
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• 2019

Electro-active polymers and dielectric elastomers have many intriguing properties that enable smart interfaces and electrically tunable optical systems, such as haptic feedback devices, artificial muscles, and expansion-tunable optical elements. These device classes are of great interest owing to their promising roles in next-generation technologies including virtual or augmented reality, human sensing and muscular enhancement, and artificial skins. In this report, we review basic principles, current state-of-the-art techniques, and future prospects of electro-active and dielectric elastomer technology. We describe chemical and physical properties of the most promising polymer substances, essential elementary architectures for artificial muscle-like functionalities, and their applications to haptic interfaces, muscular enhancement, and focus-tunable optical elements.

• Elastomers and Composites
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• 제56권2호
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• pp.57-64
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• 2021

This paper reviews recent developments and applications of dielectric elastomers (DEs) and suggests various techniques to improve DE properties. DEs as smart materials are a variety of electro-active polymers (EAPs) that convert electrical energy into mechanical energy and cause a large deformation when a voltage is applied. The dielectric constant, modulus, and dielectric loss of DEs determine the efficiency of deformation. Among these, the dielectric constant significantly affects their performance. Therefore, various recent approaches to improve the dielectric constant are reviewed, including the enhancement of polarization, introduction of microporous structures in the matrix, and introduction of ferroelectric fillers. Furthermore, the basic principles of DEs are examined, as well as their various applications such as actuators, generators, sensors, and artificial muscles.

• 한국산업융합학회 논문집
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• 제27권3호
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• pp.619-627
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• 2024

By analyzing the structure of the currently used Lead Tab tape structure, the outermost layer, low-temperature fusion functionalized olefin, was composed of pp base. To determine whether this could be used as the outermost layer of tab tape, the adhesive strength to metal foils such as copper and aluminum was measured and the adhesive strength was compared with commercially available functionalized olefin. When chlorine was grafted onto PP among the PP used in the composition, the average adhesive strength was similar to that of commercially available LT200T and superior to RE140R and LE320V. The maximum adhesive strength exceeded that of LE200T. When it comes to solvents, xylene has been shown to be better than any other. Physical methods such as substitution of other monomers, switching of additives or let-down hardly changed the adhesion of grafted PP, and the selection of PP is an important factor in preparing functional polymers.

• 청정기술
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• 제24권2호
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• pp.112-118
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• 2018

온도 변화에 따라 상 전이를 나타내는 열 감응성 고분자는 외부 온도 감응으로 태양광 투과 조절이 가능하므로 스마트 윈도우용 소재로 적용 가능하다. 넒은 온도 범위에서 사용 가능한 스마트 윈도용 열감응성 고분자의 개발은 바람직하다. 고 성능스마트 윈도우용 소재를 얻기 위하여, 단량체 N-isopropylacrylamide, 가교제 N, N'-methylenebisacrylamide (MBAm), 산화개시제 ammonium persulfate (APS)/촉매 tetramethylene diamine 및 혼합용매(물/글리세롤)을 사용하여 3차원의 열감응성(thermoresponsive) poly(N-isopropylacrylamide) (PNIPAm) 겔을 제조하였다. 본 연구에서는 혼합용매 중의 글리세롤의 함량이 가교된 PNIPAm 겔 필름의 하한임계온도(low critical solution temperature, LCST), 어는점 및 태양광의 투광도에 미치는 영향을 조사하였다. 글리세롤 함량이 0 wt%에서 10 wt%로 증가하면 PNIPAm 겔 필름의 LCST/어는점은 각각 $34.3/6.3^{\circ}C$에서 $28.2/-6.5^{\circ}C$로 감소함을 알 수 있었다. LCST보다 낮은 $25^{\circ}C$에서는 본 연구에서 합성한 모든 PNIPAm 겔 필름은 투명(광 투과)하지만 LCST보다 높은 $45^{\circ}C$에서는 불투명하다는 것을 알 수 있었다. 이러한 결과는 본 연구에서 합성한 PNIPAm 겔 소재는 $-6.5^{\circ}C$ 부근에서도 스마트 윈도우용 소재로 활용할 가능성이 높음을 알 수 있다.