• 제목/요약/키워드: Composite films

검색결과 531건 처리시간 0.031초

산화아연과 탄소나노튜브의 선형 층상 복합체의 일산화질소 가스 감지특성 (NO Gas Sensing Characteristics of Wire-Like Layered Composites Between Zinc Oxide and Carbon Nanotube)

  • 김옥길;김효진;김도진
    • 한국재료학회지
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    • 제22권5호
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    • pp.237-242
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    • 2012
  • We report on the NO gas sensing properties of Al-doped zinc oxide-carbon nanotube (ZnO-CNT) wire-like layered composites fabricated by coaxially coating Al-doped ZnO thin films on randomly oriented single-walled carbon nanotubes. We were able to wrap thin ZnO layers around the CNTs using the pulsed laser deposition method, forming wire-like nanostructures of ZnO-CNT. Microstructural observations revealed an ultrathin wire-like structure with a diameter of several tens of nm. Gas sensors based on ZnO-CNT wire-like layered composites were found to exhibit a novel sensing capability that originated from the genuine characteristics of the composites. Specifically, it was observed by measured gas sensing characteristics that the gas sensors based on ZnO-CNT layered composites showed a very high sensitivity of above 1,500% for NO gas in dry air at an optimal operating temperature of $200^{\circ}C$; the sensors also showed a low NO gas detection limit at a sub-ppm level in dry air. The enhanced gas sensing properties of the ZnO-CNT wire-like layered composites are ascribed to a catalytic effect of Al elements on the surface reaction and an increase in the effective surface reaction area of the active ZnO layer due to the coating of CNT templates with a higher surface-to-volume ratio structure. These results suggest that ZnO-CNT composites made of ultrathin Al-doped ZnO layers uniformly coated around carbon nanotubes can be promising materials for use in practical high-performance NO gas sensors.

초소수성 표면특성을 갖는 폴리프로필렌 박막형성 (Formation of Polypropylene Thin Films with Superhydrophobic Surface)

  • 박재남;신영식;이원규
    • 공업화학
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    • 제25권6호
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    • pp.598-601
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    • 2014
  • Polypropylene의 농도와 코팅 막의 건조 온도 및 나노실리카의 첨가량의 변화 등 polypropylene 박막 제조를 위한 공정 변수들이 박막의 표면 형상 및 특성에 미치는 영향을 연구하였다. Polypropylene의 농도가 30 mg/mL인 경우에 $30^{\circ}C$의 건조 온도로 90 min 동안 93 mTorr의 진공 조건으로 최대 접촉각 $154^{\circ}$를 갖는 초소수성 polypropylene 박막을 얻을 수 있었다. 용매 휘발을 위한 진공 오븐에서의 건조 온도가 증가함에 따라 박막의 거칠기가 감소하여 접촉각이 낮아지는 효과를 가져왔다. Polypropylene-실리카 복합막은 박막 내에 나노실리카의 함유량의 증가에 따라 박막 표면이 미세 다공성 구조에서 미세 구형 구조물로 변환되면서 접촉각의 증가로 초소수성 표면 특성을 보였다.

질화막 성장의 하지의존성에 따른 적층캐패시터의 이상산화에 관한 연구 (A Study on the Abnormal Oxidation of Stacked Capacitor due to Underlayer Dependent Nitride Deposition)

  • 정양희
    • 한국전기전자재료학회논문지
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    • 제11권1호
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    • pp.33-40
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    • 1998
  • The composite SiO$_2$/Si$_3$N$_4$/SiO$_2$(ONO) film formed by oxidation on nitride film has been widely studied as DRAM stacked capacitor multi-dielectric films. Load lock(L/L) LPCVD system by HF cleaning is used to improve electrical capacitance and to scale down of effective thickness for memory device, but is brings a new problem. Nitride film deposited using HF cleaning shows selective deposition on poly silicon and oxide regions of capacitor. This problem is avoidable by carpeting chemical oxide using $H_2O$$_2$cleaning before nitride deposition. In this paper, we study the limit of nitride thickness for abnormal oxidation and the initial deposition time for nitride deposition dependent on underlayer materials. We proposed an advanced fabrication process for stacked capacitor in order to avoid selective deposition problem and show the usefulness of nitride deposition using L/L LPCVD system by $H_2O$$_2$cleaning. The natural oxide thickness on polysilicon monitor after HF and $H_2O$$_2$cleaning are measured 3~4$\AA$, respectively. Two substrate materials have the different initial nitride deposition times. The initial deposition time for polysilicon is nearly zero, but initial deposition time for oxide is about 60seconds. However the deposition rate is constant after initial deposition time. The limit of nitride thickness for abnormal oxidation under the HF and $H_2O$$_2$cleaning method are 60$\AA$, 48$\AA$, respectively. The results obtained in this study are useful for developing ultra thin nitride fabrication of ONO scaling and for avoiding abnormal oxidation in stacked capacitor application.

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유리기판 위에 형성된 Al/Ni 및 TiW/Ni 다층 금속배선막의 계면 접합력 및 나노압입특성 평가 (Measurement of Adhesion Strength and Nanoindentation of Metal Interconnections of Al/Ni and TiW/Ni Layers Formed on Glass Substrate)

  • 조철민;김재호;황소리;윤여현;오용준
    • 대한금속재료학회지
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    • 제48권12호
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    • pp.1116-1122
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    • 2010
  • Metal interconnections of multilayer Al/Ni and TiW/seed-Ni/Ni were formed on glass, and the adhesion strength and nanoindentation response of the composite layers were evaluated. The Al/Ni multilayer was formed by an anodic bonding of glass to Al and subsequent electroless plating of Ni, while the TiW/Ni multilayer was fabricated by sputter deposition of TiW and seed-Ni onto glass and electroless plating of Ni. Because of the diffusion of aluminum into glass during the anodic bonding, anodically bonded glass/Al joint exhibited greater interfacial strength than the sputtered glass/TiW one. The Al/Ni on glass also showed excellent resistance against delamination by bending deformation compared to the TiW/seed-Ni/Ni on glass. From the nanoindentation experiment of each metal layer on glass, it was found that the aluminum layer had extremely low hardness and elastic modulus similar to the glass substrate and played a beneficial role in the delamination resistance by lessening stress intensification at the joint. The indentation data of the multilayers also supported superior joint reliability of the Al/Ni to glass compared to that of the TiW/seed-Ni/Ni to glass.

초고경도 Ti-Al-Si-N 나노복합체 코팅막의 미세구조 및 트라이볼로지 거동에 관한 연구 (A Study on Microstructure and Tribological Behavior of Superhard Ti-Al-Si-N Nanocomposite Coatings)

  • 허성보;김왕렬
    • 한국표면공학회지
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    • 제54권5호
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    • pp.230-237
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    • 2021
  • In this study, the influence of silicon contents on the microstructure, mechanical and tribological properties of Ti-Al-Si-N coatings were systematically investigated for application of cutting tools. The composition of the Ti-Al-Si-N coatings were controlled by different combinations of TiAl2 and Ti4Si composite target powers using an arc ion plating technique in a reactive gas mixture of high purity Ar and N2 during depositions. Ti-Al-Si-N films were nanocomposite consisting of nanosized (Ti,Al,Si)N crystallites embedded in an amorphous Si3N4/SiO2 matrix. The instrumental analyses revealed that the synthesized Ti-Al-Si-N film with Si content of 5.63 at.% was a nanocomposites consisting of nano-sized crystallites (5-7 nm in dia.) and a three dimensional thin layer of amorphous Si3N4 phase. The hardness of the Ti-Al-Si-N coatings also exhibited the maximum hardness value of about 47 GPa at a silicon content of ~5.63 at.% due to the microstructural change to a nanocomposite as well as the solid-solution hardening. The coating has a low friction coefficient of 0.55 at room temperature against an Inconel alloy ball. These excellent mechanical and tribological properties of the Ti-Al-Si-N coatings could help to improve the performance of machining and cutting tool applications.

Imprinted Graphene-Starch Nanocomposite Matrix-Anchored EQCM Platform for Highly Selective Sensing of Epinephrine

  • Srivastava, Juhi;Kushwaha, Archana;Singh, Meenakshi
    • Nano
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    • 제13권11호
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    • pp.1850131.1-1850131.19
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    • 2018
  • In this paper, an electrochemical sensor for epinephrine (EP), a neurotransmitter was developed by anchoring molecularly imprinted polymeric matrix (MIP) on the surface of gold-coated quartz crystal electrode of electrochemical quartz crystal microbalance (EQCM) using starch nanoparticles (Starch NP) - reduced graphene oxide (RGO) nanocomposite as polymeric format for the first time. Use of EP in therapeutic treatment requires proper dose and route of administration. Proper follow-up of neurological disorders and timely diagnosis of them has been found to depend on EP level. The MIP sensor was developed by electrodeposition of starch NP-RGO composite on EQCM electrode in presence of template EP. As the imprinted sites are located on the surface, high specific surface area enables good accessibility and high binding affinity to template molecule. Differential pulse voltammetry (DPV) and piezoelectrogravimmetry were used for monitoring binding/release, rebinding of template to imprinted cavities. MIP-coated EQCM electrode were characterized by contact angle measurements, AFM images, piezoelectric responses including viscoelasticity of imprinted films, and other voltammetric measurements including direct (DPV) and indirect (using a redox probe) measurements. Selectivity was assessed by imprinting factor (IF) as high as 3.26 (DPV) and 3.88 (EQCM). Sensor was rigorously checked for selectivity in presence of other structurally close analogues, real matrix (blood plasma), reproducibility, repeatability, etc. Under optimized conditions, the EQCM-MIP sensor showed linear dynamic ranges ($1-10{\mu}M$). The limit of detection 40 ppb (DPV) and 290 ppb (EQCM) was achieved without any cross reactivity and matrix effect indicating high sensitivity and selectivity for EP. Hence, an eco-friendly MIP-sensor with high sensitivity and good selectivity was fabricated which could be applied in "real" matrices in a facile manner.

초음파를 이용한 구리-은 코어-쉘의 합성 및 전도성 페이스트 적용 (Sonochemical Synthesis of Copper-silver Core-shell Particles for Conductive Paste Application)

  • 심상보;한종대
    • 공업화학
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    • 제29권6호
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    • pp.782-788
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    • 2018
  • 서브 미크론 구리-은 코어-쉘 Cu@Ag 입자를 초음파화학과 결합된 금속교환 반응으로 합성하고 인쇄용 전자부품을 위한 저렴한 전도성 페이스트 적용을 평가하였다. 코어-쉘의 합성을 위한 반응에서 코어로 사용된 $Cu_2O/Cu$ 복합체의 $Cu_2O$는 초음파화학 반응으로 Cu로 환원되고 Cu 원자는 Ag의 금속교환 반응의 환원제로 작용하여 코어 표면에 Ag가 코팅된 코어-쉘 구조를 얻었다. TEM-EDS와 TG-DSC를 이용하여 서브 미크론 입자의 코어-쉘 구조를 확인하였다. 70 wt% Cu@Ag를 용매에 분산시킨 전도성 페이스트를 결합제와 습윤제를 사용하여 제조하고, 스크린 인쇄법을 사용하여 폴리아미드 필름상에 코팅하였다. Ag 함량이 8 at%와 16 at%인 Cu@Ag 입자를 함유하는 인쇄된 페이스트 필름은 공기 중의 $180^{\circ}C$에서 소결한 후 각각 96.2와 $38.4{\mu}{\Omega}cm$의 낮은 비저항 값을 나타내었다.

신축성 접착 필름 위에 놓인 그래핀 종이의 주름 생성 (Wrinkling of Graphene Papers Placed on Stretchable Adhesive Films)

  • 김상윤;정명희;석지원
    • Composites Research
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    • 제34권2호
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    • pp.108-114
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    • 2021
  • 일반적으로 그래핀 플레이크는 산화그래핀을 화학적 또는 열적 환원 공정을 통해 환원그래핀으로 변환하여 대량 생산하고 있다. 그래핀 플레이크는 다양한 형태로 응용되는데, 그 중 진공여과를 이용한 적층 공정을 통해 종이형 필름으로 제작이 가능하다. 그래핀 종이는 신축성이 부족한 단점이 있어 신축성 소자 응용에 제약이 있다. 본 연구에서는 신축성이 있는 그래핀 종이를 제작하기 위하여, 그래핀 종이에 주름을 만들었다. 신축성이 뛰어난 접착 필름을 미리 늘린 후, 그 위에 그래핀 종이를 붙이고, 접착 필름을 원래 상태로 놓아 주어 그래핀 종이에 주름을 만들었다. 이 때, 접착 필름에 가하는 당김 정도 및 젖은 상태에 따라 주름의 형상이 변하는 것을 실험적으로 관찰하였다. 특히, 그래핀 종이와 접착 필름의 전단 탄성 계수 차에 의하여 주름의 주기가 바뀌는 현상을 관찰하였다.

Diglycidyl ether of terephthalylidene-bis-(4-amino-3-methylphenol)의 열적 성질에 대한 연구 (Thermal Properties of Diglycidyl Ether of Terephthalylidene-bis-(4-amino-3-methylphenol))

  • 현하늘;최지우;조승현
    • Composites Research
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    • 제35권2호
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    • pp.53-60
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    • 2022
  • 본 연구에서 액정성 에폭시인 Diglycidyl ether of terephthalylidene-bis-(4-amino-3-methylphenol) (DGETAM)을 사용해 경화제로는 아민계 경화제인 4,4'-diaminodiphenylethane (DDE)와 양이온 개시제인 N-benzylpyrazinium hexafluoroantimonate (BPH)를 사용하여 필름의 형태로 샘플을 제작하였다. 합성의 확인을 위하여 1H-NMR과 FT-IR을 사용하였고, DSC와 POM을 이용하여 DGETAM의 액정성을 확인하고, LFA를 사용하여 샘플의 열전도도를 측정하였다. 활성화 에너지는 TGA를 사용하여 등온 열분해를 진행해 측정한 데이터를 토대로 Arrhenius 식을 사용하여 구하였다. 에폭시 필름의 열전도도를 측정한 결과 DDE를 사용하였을 때, 더 높은 열전도도를 나타내었고, 5% 분해시 BPH를 사용한 필름과 유사한 활성화 에너지를 나타내는 것으로 보아, 열전도도가 열적 안정성에 영향을 미치는 것을 확인할 수 있었다.