http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Replica molding of vertically aligned liquid crystalline polymer microstructures
위정재,( Hangbo Zhao ),( Davor Copic ),( Alvin Orbaek White ),( Sanha Kim ),( A. John Hart ) 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Molecularly anisotropic polymers can be manufactured into a wide variety of forms capable of actuation upon application of external stimuli. In particular, incorporation of the liquid crystal molecules in polymeric networks enables facile route to align mesogenic units within microstructures. Most studies of current thermomechanical actuation of liquid crystalline polymers have used millimeter-scale and larger shapes, and only a few studies reported thermally responsive liquid crystal polymer microstructures. Here we present the thermomechanical response of glassy azobenzene-functionalized liquid crystalline polymer networks in micropillar geometries. Large-arrays of uniform polymer microstructures are fabricated by replica molding of using a polydimethylsiloxane (PDMS) template, and the molecular orientation of the polymer is manipulated by applying a magnetic field during photocuring the molten monomer mixture in the mold. We discuss how the micropillar and liquid crystal geometry influence the stimuli response from the highly crosslinked polymer network.
Chen, Yu-Chih,Baac, Hyoung Won,Lee, Kyu-Tae,Fouladdel, Shamileh,Teichert, Kendall,Ok, Jong G.,Cheng, Yu-Heng,Ingram, Patrick N.,Hart, A. John,Azizi, Ebrahim,Guo, L. Jay,Wicha, Max S.,Yoon, Euisik American Chemical Society 2017 ACS NANO Vol.11 No.5
<P>Considerable evidence suggests that self-renewal and differentiation of cancer stem-like cells, a key cell population in tumorgenesis, can determine the outcome of disease. Though the development of microfluidics has enhanced the study of cellular lineage, it remains challenging to retrieve sister cells separately inside enclosed microfluidics for further analyses. In this work, we developed a photomechanical method to selectively detach and reliably retrieve target cells from enclosed microfluidic chambers. Cells cultured on carbon nanotube polydimethylsiloxane composite surfaces can be detached using shear force induced through irradiation of a nanosecond-pulsed laser. This retrieval process has been verified to preserve cell viability, membrane proteins, and mRNA expression levels. Using the presented method, we have successfully performed 96-plex single-cell transcriptome analysis on sister cells in order to identify the genes altered during self-renewal and differentiation, demonstrating phenomenal resolution in the study of cellular lineage.</P>
탄소나노튜브-금속산화물 나노와이어의 3차원 혼성 나노구조 형성 및 응용
옥종걸(Jong G. Ok),A. John Hart,L. Jay Guo 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
We present the assembly and application of three-dimensional (3D) hybrid nanoarchitectures comprising carbon nanotubes (CNTs) and metal oxide (MOx) nanowires such as zinc oxide and vanadium oxide. The MOx nanowires are hierarchically assembled onto the surface of aligned or textured CNT constructs via the step-wise chemical vapor deposition (CVD) process at the temperature CNTs are free from oxidative degradation. Since the conformal highdensity MOx nanowires can be directly connected to highly conducting CNT framework over large interfacial area, the electrical response originating from functional MOx upon external stimuli can be rapidly and efficiently collected through the CNT framework, leading to many applications ranging from fast-responsive sensors to energy converters.
Park, Sei Jin,Ok, Jong G.,Park, Hui Joon,Lee, Kyu-Tae,Lee, Jae Hyuk,Kim, Jeong Dae,Cho, Eikhyun,Baac, Hyoung Won,Kang, Shinill,Guo, L. Jay,Hart, A. John Elsevier 2018 Carbon Vol.129 No.-
<P><B>Abstract</B></P> <P>The unique properties of carbon nanotubes (CNTs) allow them to be used in various optical applications, such as ultra-dark surfaces, bolometers, metamaterial cloaks, and anisotropic absorbers. In particular, organization of CNTs with controlled density at the sub-micrometer scale could enable new strategies to engineer optically active surfaces. Here, we present a new strategy to engineer the density-dependent optical properties of CNT forests by patterning of catalyst film via nanoimprint lithography (NIL) followed by atmospheric pressure chemical vapor deposition (CVD) synthesis of CNTs. Via this approach, we demonstrate atmospheric pressure growth of CNT structures with widths of 80–350 nm. These structures form self-supporting arrays with height exceeding 500 μm, representing aspect ratios well over 1000:1. Optical attenuation measurement places the density of NIL patterned forests to be a fraction of the density of unpatterned CNT forests, confirming that the CNT density is effectively controlled by the catalyst coverage. The infrared absorbance measurements corroborate the density control, and Kramers-Kronig analysis shows that the refractive indices of the NIL patterned CNT forests are tunable in the range of 1–1.8.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>