서지주요정보
Molecular ordering of organic supramlecules at the ultra-thin film = 초박막상태에서의 유기초분자의 분자 배향에 관한 연구
서명 / 저자 Molecular ordering of organic supramlecules at the ultra-thin film = 초박막상태에서의 유기초분자의 분자 배향에 관한 연구 / Dong-Ki Yoon.
저자명 Yoon, Dong-Ki ; 윤동기
발행사항 [대전 : 한국과학기술원, 2003].
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소장정보

등록번호

8014071

소장위치/청구기호

학술문화관(문화관) 보존서고

MCBE 03022

SMS전송

도서상태

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초록정보

The molecular ordering of the synthesized supramolecules is strongly affected by the functionality, molecular shape and surface anchoring. The thermal analysis was performed by differential scanning calorimetry (DSC). Synchrotron X-ray diffraction (XRD), polarized optical microscopy (POM) results show that the asymmetric fan-shaped second generation dendrimer containing a $CO_2C_3H_7$ core group of the cylinder and dodecyl ($C_{12}H_{25}$) alkyl tails exhibits hexagonal columnar mesophase upon cooling from isotropic phase. Transmission electron microscopy (TEM) images show that the columns are strongly affected by the substrates and film thickness: The columnar aligned perpendicular to hydrophobic substrate, and it aligned parallel to the hydrophilic surface. Different morphologies are encountered depending on the thickness. Thick films of such a material exhibit highly ordered hexagonal structure where the columns are oriented either parallel or perpendicular depending on the substrate. However, at the ultrathin films state, low surface energy planes are identified through examination of the morphology of the fan-shaped dendrimer, which contain hexagonally shaped holes on a free surface. The film forms into pinholes (with sharp edges) that have orientations related by an approximate hexagonal symmetry. The predominant direction of the hole edges corresponds to the (10) molecular lattice direction. In order to understand self-assembling mechanism of the planar ordering, we investigate the surface texture of Langmuir-Blodgett monolayers and multilayers of the dendrimer at the air-water interface. Surface pressure-area ($\pi$-A) isotherm and Brewster angle microscopy (BAM) measurements show that the molecule forms a stable monolayer on a water surface with two phase transitions (gaseous phase → expanded phase → condensed phase). The electron diffraction (ED) patterns, transmission electron microscopy (TEM) and atomic force microscopy (AFM) images of the condensed monolayers clearly reveal that the molecule forms edge-on-oriented monolayers with hexagonal packing on the water surface, suggesting fractional cylindrical configuration at the air-water interface. Upon further compression, the condensed monolayer is transformed into a multilayer, and the interfacial structure becomes planar morphology. These results demonstrate the origin of planar alignment of self-assembled dendrimers on water surface.

서지기타정보

서지기타정보
청구기호 {MCBE 03022
형태사항 vii, 65 p. : 삽도 ; 26 cm
언어 영어
일반주기 저자명의 한글표기 : 윤동기
지도교수의 영문표기 : Hee-Tae Jung
지도교수의 한글표기 : 정희태
학위논문 학위논문(석사) - 한국과학기술원 : 생명화학공학과,
서지주기 Includes references
주제 Organic supramolecule
Molecular oredering
Ultrathin film
유기초분자
분자 배향
초박막
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