• 공업화학
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• 제34권4호
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• pp.347-356
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• 2023

액정 엘라스토머 섬유는 1차원 형태로서 소프트 로봇, 생체모방 구동기 등의 다양한 분야에서 광범위하게 응용되고 있다. 액정 엘라스토머는 액체의 유동성과 고체의 질서도 그리고 고무의 탄성을 포함하며 이를 바탕으로 한 자극-응답성을 가지고 있다. 특히, 형상가변 측면에서 열, 빛, 전기장, 자기장 등의 다양한 자극에 대한 응답성을 프로그래밍하여 사용하면 높은 자유도와 더불어 물건 들어올리기, 꼬임, 회전 등 다양한 움직임을 구현할 수 있다. 따라서, 액정 엘라스토머 섬유는 인공근육, 소프트로봇, 웨어러블 기술, 센싱 기술 등 다양한 분야로의 응용가능성을 가지고 있다. 이런 액정 엘라스토머 섬유의 연구는 기존 단순 섬유를 넘어서는 다양한 기능성을 포함할 수 있는 스마트 소재로서 도래한 4차 산업에서 다양한 분야에 활용도가 높다고 평가된다. 본 총설에서는 액정 엘라스토머 섬유의 구조 및 기본 특성에 대해 소개하고, 배향 기반 제작법과 이를 이용한 인공근육, 스마트 패브릭, 소프트 로봇 등, 다양한 응용에 대해 최신 연구 동향을 소개한다.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.1-14
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• 2023

The overuse of pesticides in agricultural sectors exposes people to food contamination. Pesticides are toxic to humans and can have both acute and chronic health effects. To protect food consumers from the adverse effects of pesticides, a rapid monitoring system of the residues is in dire need. Molecularly imprinted polymer (MIP) on a screen-printed electrode (SPE) is a leading and promising electrochemical sensing approach for the detection of several residues including pesticides. Despite the huge development in analytical instrumentation developed for contaminant detection in recent years such as HPLC and GC/MS, these conventional techniques are time-consuming and labor-intensive. Additionally, the imprinted SPE detection system offers a simple portable setup where all electrodes are integrated into a single strip, and a more affordable approach compared to MIP attached to traditional rod electrodes. Recently, numerous reviews have been published on the production and sensing applications of MIPs however, the research field lacks reviews on the use of MIPs on electrochemical sensors utilizing the SPE technology. This paper presents a distinguished overview of the MIP technique used on bare and modified SPEs for the detection of pesticides from four recent publications which are malathion, chlorpyrifos, paraoxon and cyhexatin. Different molecular imprint routes were used to prepare these biomimetic sensors including solution polymerization, thermal polymerization, and electropolymerization. The unique characteristics of each MIP-modified SPE are discussed and the comparison among the findings of the papers is critically reviewed.

• 센서학회지
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• 제29권2호
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• pp.100-104
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• 2020

Thus far, several in vivo biosensing platforms have been proposed to measure the mechanical contractility of cultured cardiomyocytes. However, the low sensitivity and screening rate of the developed sensors severely limit their practical applications. In addition, intensive research and development in cardiovascular disease demand a high-throughput drug-screening platform based on biomimetic engineering. To overcome the drawbacks of the current state-of-the-art methods, we propose a high-throughput drug-screening platform based on 16 functional high-sensitivity well plates. The proposed system simulates the physiological accuracy of the heart function in an in vitro environment. We fabricated 64 cantilevers using highly flexible and optically transparent silicone rubber and placed in 16 independent wells. Nanogrooves were imprinted on the surface of the cantilever to promote cell alignment and maturation. The adverse effects of the cardiovascular drugs on the cultured cardiomyocytes were systematically investigated. The 64 cantilevers demonstrated a highly reliable and reproducible mechanical contractility of the drug-treated cardiomyocytes. Real-time high-throughput screening and simultaneous evaluation of the cardiomyocyte mechanical contractility under multiple drugs verified that the proposed system could be used as an efficient drugtoxicity test platform.

• 한국세라믹학회지
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• 제44권4호
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• pp.198-201
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• 2007

Multi-walled carbon nanotube (M-CNT)/Nafion nanocomposites were prepared by solution casting to elucidate the effect of M-CNT addition, from 0 to 7 wt%, on the viscoelastic behavior of the composites. The M-CNT bundles induced by the Nafion polymer were determined to be uniformly distributed for the 1 wt% M-CNT/Nafion nanocomposites. The 1 wt% M-CNT/Nafion composite exhibited the highest blocking stress of 2.3 kPa due to its high elastic modulus of 0.485 GPa. From a dynamic mechanical analysis, the 1 wt% M-CNT had the highest storage and loss moduli compared with the other samples in all frequency and temperature ranges. From the storage modulus data, the M-CNT loaded composites had similar $T_g$ values near $120^{\circ}C$. The glass transition temperatures of the M-CNT loaded composites were $120^{\circ}C$ (1 wt%), $117^{\circ}C$ (3 wt%), $117^{\circ}C$ (5 wt%), and $135^{\circ}C$ (7 wt%), suggesting that the effect of the M-CNTs on the Nafion film begins at 1 wt%. Thus, it has been concluded that the 1 wt% M-CNT disported composite is attractive for actuator applications.

• KSTLE International Journal
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• 제7권1호
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• pp.14-17
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• 2006

In this paper, we report on the replication of surface topography of natural leaf of Lotus onto thin polymeric films using a capillarity-directed soft lithographic technique. PDMS molds were used to replicate the surface. The replication was carried out on poly(methyl methacrylate) (PMMA) film coated on silicon wafer. The patterns so obtained were investigated for their friction properties at micro-scale using a ball-on-flat type micro-tribo tester, under reciprocating motion. Soda lime balls (1 mm diameter) were used as counterface sliders. Friction tests were conducted at a constant applied normal load of $3000{\mu}N$ and speed of 1mm/s. All experiments were conducted at ambient temperature ($24{\pm}1^{\circ}C$) and relative humidity ($45{\pm}5%$). Results showed that the patterned samples exhibited superior tribological properties when compared to the silicon wafer and non patterned sample (PMMA thin film). The reduced real area of contact projected by the surfaces was the main reason for their enhanced friction property.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.495-495
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• 2011

Miniaturized sensors capable of both sensitive and selective real-time monitoring of target analytes are tremendously valuable for various applications ranging from hazard detection to medical diagnostics. The wide-spread use of such sensors is currently limited due to insufficient selectivity for target molecules. We developed selective nanocoatings by combining trinitrotoluene (TNT) receptors bound to conjugated polydiacetylene (PDA) with single-walled carbon nanotube-field effect transistors (SWNT-FET). Selective binding events between TNT molecules and phage display derived TNT receptors were effectively transduced to sensitive SWNT-FET conductance sensors through the PDA coating. The resulting sensors exhibited unprecedented 1 fM sensitivity toward TNT in real time, with excellent selectivity over various similar aromatic compounds. Our biomimetic receptor coating approach may be useful for the development of sensitive and selective micro and nanoelectronic sensor devices for various other target analytes.

• 방사선산업학회지
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• 제2권1호
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• pp.1-7
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• 2008

Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as biomimetic actuators and artificial muscles. In this study, poly (vinyl alcohol)(PVA) grafted acrylic acid monomer (PVA-g-AAc) hydrogels were prepared by $^{60}Co$ ${\gamma}-ray$ irradiation and their properties such as degree of grafting and weight swelling in electrostimulation as an artificial muscle and actuator were investigated.