Hydroxyl radical (OH radical) is the most harmful free radical amongst the Reactive Oxygen Species (ROS) responsible for numerous diseases of DNA damage like mutagenesis, carcinogenesis and ageing. Therefore, it is important to find a suitable scavenger for OH radical. In the present contribution, we aim to investigate the ability of pristine armchair-SWCNT and B/N/P-doped armchair-SWCNT to scavenge OH radicals using DFT calculations. The calculations reveal that the B/Pdoped armchair-SWCNTs can act as a better scavenger for OH radical compared to pristine armchair-SWCNT but N-doped armchair-SWCNT does not act as a better scavenger for OH radical compared to pristine armchair-SWCNT. Furthermore, the developed scavenger is examined in terms of large-scale availability, biocompatibility, conductivity, stability and reactivity. For both in vivo and in vitro studies, the work is found to useful for enhancing SWCNT as a free radical scavenger.

The central theme of this work is the synthesis of single-walled carbon nanotubes (SWCNTs) through the chemical vapor deposition method (CVD). Single-walled carbon nanotubes are synthesized using catalyst-chemical vapor deposition of acetylene at 750 °C temperature. X-ray diffraction study gives a characteristic peak (002) at 26.55° corresponding to the existence of carbon nanotube confirms that the particles are crystalline in nature and hexagonal phase. An SEM and HRTEM outcome gives surface morphology of SWCNTs. The elemental composition was confirmed by EDAX. The ideal concentration of single-walled carbon nanotubes was used to design a novel electrochemical sensor for determining paracetamol (PA) using cyclic voltammetry. Electrochemical determination of paracetamol is described using a single-walled carbon nanotube modified carbon paste electrode (SWCNT/MCPE). The SWCNT/MCPE was used in this study to detect paracetamol electrochemically at pH 7.2 in a 0.2 M PBS with a scan rate of 50 mV s− 1. A single-walled nanotube modified carbon paste electrode was used to develop a sensitive and selective electrochemical technique for the detection of PA. The SWCNT/MCPE showed excellent electrocatalytic activity towards the oxidation of paracetamol in phosphate buffer solution. Therefore, with increased oxidation currents, the voltammetric responses of paracetamol at the bare carbon paste electrode are organized within cyclic voltammetric peaks.

We report the comparative study of electronic and optical properties of (6,1) SWCNT from GGA and DFT-1/2 methods. (6,1) SWCNT is a low-bandgap semiconductor, which falls within ( n1 − n2)/3≠ integer. The calculated bandgaps are 0.371 eV and 0.462 eV from GGA and DFT-1/2, respectively. Thus, DFT-1/2 enhanced the electronic bandgap by 24.52%. From both GGA and DFT-1/2 approaches (6,1) SWCNT exhibits an indirect bandgap along Γ − Δ symmetry. However, the percentage change in direct–indirect bandgap is negligibly small, i.e., 4.1% and 3.7% from GGA and DFT-1/2, respectively. The refractive index measured along x-axis ( n x ) approaches unity, indicating transparent behaviour, while that along z-axis ( n z ) goes as high as ∼3.82 for photon energy 0.0 − 0.15 eV, exhibiting opaque behaviour. Again, the value of n z drops below unity at photon energy ∼0.18 eV and again approaches ∼ 1 for higher energy ranges. The optical absorption is highly anisotropic and active within the infrared region.

The purpose of this study is to fabricate an ophthalmic lens by copolymerizing two types of carbon nanotubes and hydrophilic hydrogel lens materials, and to investigate its application as an ophthalmic lens material by analyzing its physical properties and antimicrobial effect. For polymerization, HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate), a crosslinking agent, and AIBN (azobisisobutyronitrile), an initiator, are used as a basic combination, and a single-walled carbon nanotube and a single-walled, carboxylic-acid-functionalized carbon nanotube are used as additives. To analyze the physical properties, the water content, refractive index, breaking strength, and antimicrobial effect of the fabricated lenses are measured. The fabricated lenses satisfies all the basic properties of the basic hydrogel ophthalmic lens. The water content increases with increasing amount of additive and decreases with addition of 0.2% ratio of nanoparticles. The refractive index is inversely proportional to the water content result. As a result of the antimicrobial test of the fabricated lens, the addition of carbon nanotubes shows an excellent antimicrobial effect. Therefore, it is considered that the fabricated lens can be applied as a functional material for basic ophthalmic hydrogel lenses.

본 연구는 탄소나노튜브/보강섬유/폴리머 복합 쉘에 대한 동적응답을 다루었다. 단일벽 탄소나노튜브, 유리섬유 및 에폭시 레진으로 구성된 3단계 복합구조이며, 유효 물성값은 멀티스케일 해석을 통하여 산정하였다. 유한요소 프로그램인 ABAQUS를 적용하여 다양한 탄소나노튜브 함유비율, 적층각도, 곡률 및 중앙 개구부의 다양한 변화에 대한 동적응답 및 상호 작용을 분석하였다. 본 연구는 원통형 복합쉘의 동적 하중에 의한 처짐을 감소시킬 수 있는 변수들의 중요성을 보여주었다.

본 연구에서는 중앙 개구부를 갖는 카본나노튜브/유리섬유/폴리머 합성 복합 적층쉘을 다루었다. 수정된 Halpin-Tsai 모델과 마이크로 역학적 접근방법은 단일벽 탄소나노튜브의 합성 비율에 따른 탄성적 물성변화를 추정하기 위하여 적용되었다. 유한요소 해석을 통하여 쉘의 고유진동 및 모드 특성을 분석하였다. 탄소나노튜브의 무게 비율, 보강섬유 각도, 개구부 크기, 고 유진동수 및 고유모드의 상관관계를 규명하였다. 개구부를 갖는 경우와 갖지 않는 경우에 대하여 곡률 변화에 따른 기존 문헌 과의 비교를 통하여 본 연구결과를 검증하였다. 본 연구결과는 고유진동 특성에 영향을 미치는 탄소나노튜브 보강의 중요성을 보여준다.

Recently, functionalization of construction materials using nano materials is being studied in domestic and overseas. In this study, functionalization of cement composites using excellent mechanical characteristics, electrical and thermal conductivity characteristics was carried out. The basic study on the heat characteristics of cement mortar containing Single-walled Carbon Nano Tube(SWCNT), one of the CNT types, has been carried out and this study is aimed to verify whether heat characteristics is effective at low content mixing. The experimental parameters were selected as CNT content, curing age, and supplied voltage. The size of specimens was 50 x 50 x 50mm3 and three specimens were fabricated. As a result, heat characteristics of the SWCNT cement mortar was confirmed even at a low CNT content. As the curing progressed, it was confirmed that heat generation effect was low. But it was confirmed that the heat characteristics were sufficiently exhibited when 100V or more voltage was supplied.

Due to their novel properties, GaN based semiconductors and their nanostructures are promising components in a wide range of nanoscale device applications. In this work, the gallium nitride is deposited on c-axis oriented sapphire and porous SWCNT substrates by molecular beam epitaxy using a novel single source precursor of Me2Ga(N3)NH2C(CH3)3 with ammonia as an additional source of nitrogen. The advantage of using a single molecular precursor is possible deposition at low substrate temperature with good crystal quality. The deposition is carried out in a substrate temperature range of 600-750˚C. The microstructural, structural, and optical properties of the samples were analyzed by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and photoluminescence. The results show that substrate oriented columnar-like morphology is obtained on the sapphire substrate while sword-like GaN nanorods are obtained on porous SWCNT substrates with rough facets. The crystallinity and surface morphology of the deposited GaN were influenced significantly by deposition temperature and the nature of the substrate used. The growth mechanism of GaN on sapphire as well as porous SWCNT substrates is discussed briefly.

Semiconducting metal oxides have been frequently used as gas sensing materials. While zinc oxide is a popular material for such applications, structures such as nanowires, nanorods and nanotubes, due to their large surface area, are natural candidates for use as gas sensors of higher sensitivity. The compound ZnO has been studied, due to its chemical and thermal stability, for use as an n-type semiconducting gas sensor. ZnO has a large exciton binding energy and a large bandgap energy at room temperature. Also, ZnO is sensitive to toxic and combustible gases. The NO gas properties of zinc oxide-single wall carbon nanotube (ZnO-SWCNT) composites were investigated. Fabrication includes the deposition of porous SWCNTs on thermally oxidized SiO2 substrates followed by sputter deposition of Zn and thermal oxidation at 400˚C in oxygen. The Zn films were controlled to 50 nm thicknesses. The effects of microstructure and gas sensing properties were studied for process optimization through comparison of ZnO-SWCNT composites with ZnO film. The basic sensor response behavior to 10 ppm NO gas were checked at different operation temperatures in the range of 150-300˚C. The highest sensor responses were observed at 300˚C in ZnO film and 250˚C in ZnO-SWCNT composites. The ZnO-SWCNT composite sensor showed a sensor response (~1300%) five times higher than that of pure ZnO thin film sensors at an operation temperature of 250˚C.