• Bulletin of the Korean Chemical Society
• /
• v.25 no.3
• /
• pp.351-356
• /
• 2004

Selected MPEG-b-PDLLA block copolymers have been synthesized by ring-opening polymerization with systematic variation of the chain lengths of the resident hydrophilic and hydrophobic blocks. The size and shape of the micelles that spontaneously form in solution are then controlled by the characteristics of the block copolymer template. All the materials prepared in this study showed the tunable pore size of 20-80 ${\AA}$ with the increase of hydrophobic chain lengths and up to 660 $m^2$/g of specific surface area. The formation mechanism of these nanoporous structures obtained by controlling the micelle size has been confirmed using both liquid and solid state $^{13}C\;and\;^{29}Si$ NMR techniques. This work verifies the formation mechanism of nanoporous structures in which the pore size and wall thickness are closely dependent on the size of hydrophobic cores and hydrophilic shells of the block copolymer templates.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.2
• /
• pp.193-194
• /
• 2006

• Polymer Science and Technology
• /
• v.21 no.6
• /
• pp.528-536
• /
• 2010

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.214-214
• /
• 2013

Ion beam sputtering (IBS) by collision of energetic ions at surfaces is one of the representative methods for physical self-assembly. It is in spotlight as an easy tool to make nano structures in various sizes and shapes by controlling physical variablesWe investigate nano patterning on graphite. We found well-ordered nano ripple patterns after sputtering under the oblique angle and mean wavelengths of these ripples could be controlled as ion fluence increases from sub-10 nm to 80 nm. Each nano ripple is terminated by nano buds, which look like a cotton bud. We also examined the formation of various patterns on graphite by sputtering during swinging the sample at a constant angular velocity that have been never reported.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.632-632
• /
• 2013

We generated single-crystal organic nanowire arrays using a direct printing method (liquidbridge- mediated nanotransfer molding) that enables the simultaneous synthesis, alignment and patterning of nanowires from molecular ink solutions. Using this method, single-crystal organic nanowires can easily be synthesized by self-assembly and crystallization of organic molecules within the nanoscale channels of molds, and these nanowires can then be directly transferred to specific positions on substrates to generate nanowire arrays by a direct printing process. The position of the nanowires on complex structures is easy to adjust, because the mold is movable on the substrates before the polar liquid layer, which acts as an adhesive lubricant, is dried. Repeated application of the direct printing process can be used to produce organic nanowire-integrated electronics with twoor three-dimensional complex structures on large-area flexible substrates. This efficient manufacturing method is used to fabricate all-organic nanowire field-effect transistors that are integrated into device arrays and inverters on flexible plastic substrates.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.267-267
• /
• 2013

Band engineering of a nanowire is related to the question what is the minimum size of a nanowire-based device. At the subnanometer scale, there has been a long standing problem whether it is possible to both control an energy band of an isolated nanowire by a dopant and measure it using angle-resolved photoemission spectroscopy (ARPES). This is because an extra atom in the subnanometer wire plays as a defect rather than a dopant and it is challenging to assemble isolated subnanometer wires into an array for an ARPES measurement. We demonstrate that only one of multiple metallic subnanometer wires canbe controlled electronically by a dopant maintaining the whole metallic bands of other wires, which was observed directly by ARPES. Here,the multiple metallic subnanometer wires were produced on a stepped Si(111) surface by a self-assembly method. The selective band engineering proves that the selectively-controlled metallic wire is nearly isolated electronically from other metallic wires and an electronic structure controlcan be realized down to subnanometer scale.

• Current Photovoltaic Research
• /
• v.2 no.3
• /
• pp.84-87
• /
• 2014

Protection of solar cell surface is important to prevent from dust, pollen, sand, etc. Therefore, development of large area antifouling film is urgent for high performance of solar cells. The surface of silica spheres was modified to fabricate large area antifouling film. The surface of monodisperse silica spheres has been modified with 3-(trimethoxysilyl) propylmethacrylate (TMSPM) to fabricate large area photonic crystal. Although the surface modification of silica spheres with TMSPM has been failed for the base catalyst, the second trial using acid catalyst showed the following results. The FTIR absorption peak at $1721cm^{-1}$ representing C=O stretching vibration indicates that the TMSPM was attached on the surface of silica spheres. The methanol solution comprised of the surface modified silica spheres (average diameter of 380 nm) and a photoinitiator was poured in the patterned silicon wafer with the dimension of 10 cm x 10 cm and irradiated UV-light during the self-assembly process. The result showed large area crack and defect free nanostructures.

• Proceedings of the Korea Technology Innovation Society Conference
• /
• 2001.05a
• /
• pp.271-284
• /
• 2001

Nanotechnology arises from the exploitation of physical, chemical,and biological properties of systems that are intermediate in size between isolated atoms/molecules and bulk materials, where phenomena length scales become comparable to the size of the structure. In addition nanotechnology implies direct control of materials and devices on molecular and atomic scale, including fabrication of functional nanostructures with desired properties, synthesis and processing of nanoparticles, self-assembly, use of quantum effects, etc. This article is a collection of Informations of trend of research and development in the field of nanotechnology in U.S., EU, Japan and Korea. And we would like to include some idea to decide the direction and the strategy for the investment for nanotechnology.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.315-317
• /
• 2009

We report the preparation of novel nanofiber organic semiconductors that can be utilized as the active channel materials in the field effect transistors (FETs). The nanofibers produced by the electrospinning reveals the excellent performances (mobility ~ 0.16 $cm^2$/V) due to thier highly ordered molecular packing in the polymer matrix.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.900-903
• /
• 2007

We introduce non-contact surface modification using trimethylchlorosilane (TMCS) for thin film transistor application. The surface is not contacted to the TMCS solution because it is vaporized at room temperature. The hydrophobic surface with contact angle $of\;{\sim}\;70^{\circ}$ can be achieved by the transfer of TMCS using a PDMS mold.