Structures and Properties of Brush Polymers Bearing Biomolecules

DoctorPolymer materials have several advangtages such as easy process at low cost, high flexibility, high mechanical strength, and good scalability. Furthermore, their properties can be controlled by various syntheic methods. Through chemical bonding of specific molecules to the polymer backbone, side chain or functional groups, the function of polymer can be changed. First brush polymers were reported as aliphatic polymers with n-alkyl side chains in the 1940s.The n-alkyl side chains have self-assembly character. The macroscopic properties on film surfaces were managed through control of microscopic structures in polymer structure by self-assembly character. In consideration of high potential application of various brush polymer system, such as biomaterials, microelectronics, solar cells, adhesives, and gas separation membranes, the structure analysis with surface characteristic is very important. In the area of biomaterials, biomolecule-mimicking brush polymers may be useful in a variety of solid forms as biocompatible coating materials, tissue culture materials, biomedical sensor materials, protein separation membranes, and gene delivery carriers. Most of these applications require formation of nanoscale thin films with control over the nanostructures.In Chapter II, A series of well-defined brush polymers with quaternary ammonium were synthesized. These polymers have self assembled structure by interaction of quaternary ammonium groups and from multi-layer structures, providing hydrophilic cationic surfaces. Because of quaternary ammonium groups and long brush alkyl chain, the polymer films have bactericidal properties and selective protein adsorption properties by positively charged surfaces. However, in vitro and in vivo result of each polymers were different. The polymer which has high amount of QA showed unfavorable environment to cells but the polymer with a small number of quaternary ammonium showed good biocompatibility. These results indicate that the control of surface characters by functional groups of brush polymers and self assembled characters are important for biomedical applications.In Chapter III, X-ray reflectivity (XR) study of brush polymers with various number of bristle ends incorporating phosphorylcholine (PC) moieties was performed in thin films supported on silicon substrates. As a result of self assembled structure, Bragg reflections were observed and a quantitative analysis was conducted for multilayer structure using Parratt formalism. This analysis provides detail information about structure and interface across the film thickness of the lamellar structure with varying mole fraction of PC moieties. The structures of the polymer thin films were extensively changed as adding the PC moieties and increasing mole fraction at the alkyl side end. As a result, highly ordered multilayer lamellar structure was leaded.In Chapter IV, In this study, neutron reflectivity study of brush polymers with bristle ends incorporating phosphocholine (PC) moieties was performed in dry, liquid, and protein solution on quartz substrate. Before neutron reflectivity measurements, X-ray reflectivity measurements were carried out to confirm the multilayer structure of each film and film conditions. As a result of self-assembled structure, strong Bragg peaks were observed in both X-ray reflectivity and neutron reflectivity measurement. Though certain Bragg peaks in liquid condition was not shown because of water swelling, surface of polymer films were shown excellent functional character. Indeed, thickness variation by water sorption was also well displayed difference of functionalized polymers. As a result, protein resist surface was leaded by self assembled structure.In Chapter V, In this study XR study of brush polymers was performed on water surface. By the mixing of hydrophilic and hydrophobic group, different structure transitions were shown during surface compression. The thickness of LB monolayer was confirmed by XR and structure model was supported by IR measurement. Alkyl chain packing and disordering was observed and hydrogen bonding between polymer and water was also observed. Inverse structure and double layer structure were suggested for each polymer at high surface pressure area to agreement with experiment results. As a result, unique LB monolayer structure was purchased.In Chapter VI, XR studies were conducted to characterize the thin films of brush polymers with various number of bristle ends incorporating 0, 25, 50, 75 and 100 % of quaternary ammonium (QA). The films were coated on silicon wafer substrates by spin-coating. Because of interaction of QA ends and alkyl chain, each polymer has self assembled multi layer structure and Bragg reflections were observed. The results indicate that structure of polymer films were dramatically changed as adding the QA ends. Especially, due to the carboxylic group between alkyl chain and QA, bent alkyl chain structures with crystalline QA groups or stand alkyl chain structure with interdigitate QA groups were presented. These analysis provide detail information about structure and interface across the film thickness of the lamellar structures

Brush Polymers Bearing Various Glycine Derivatives and Its Biocompatibility with Self-Assembled Structure

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A method for evaluating the joint venture project from the point of view of local partner

학위논문(석사) - 한국과학기술원 : 산업공학과, 1975, [ iv, 75 p. ]정부의 외자도입정책하에서 선진국의 자본 및 기술을 도입하고, 해외시장에서의 국제경쟁력을 제고하기 위한 하나의 방안으로서 우리나라 기업은 그간 선진국 기업과의 합작투자사업을 계획, 추진해 왔다. 합작투자사업에서 자본도입측인 국내파트너는 자본수출측인 외국파트너에 비해서 불리한 조건을 감수해야 하는 입장에 있음에도 불구하고 합작투자만 하면 모든 문제가 해결될 수 있는 것처럼 잘못 생각하는 경향이 없지 않으며, 합작안의 평가도 경영자의 주관적인 판단이나 경험에 크게 의존하고 있다. 본 논문은 선진국기업과 신규 합작투자사업을 추진하려는 개발도상국의 국내측 파트너 입장에서 합작투자안을 평가하기 위한 체계적인 방법을 제시하려는데 그 목적이 있다. 본 논문은 합작안의 분석자나 의사결정자가 기존의 기업투자이론으로 합작투자안을 평가하려 할 때 당면하게 될 문제점을 명확히 규명하고 이에 대한 하나의 해결방안으로서 요인분석에 의한 합작선의 평가방법을 제안하였다. 기존의 투자 분석방법이 가지고 있는 결함은 다음 2가지로 요약 될 수 있다. 1) 위험과 불확실성을 비 현실적으로 평가하고 있다. 2) 수익성 이외의 제 요인을 명확하a}? 고려하지 않고 있다. 본 논문에서 제안한 방법은 다음과 같다. 1) 합작투자사업의 성공에 중대한 영향을 미칠 요인을 선정한다. 2) 요인간의 상대적 중요도를 평가하여 요인별 중요도 평점을 할당한다. 3) 각 파트너가 이들 요인을 만족시키는 정도를 평가하여 각파트너별 평점을 산출한다.한국과학기술원 : 산업공학과

Synchrotron X-ray and Neutron Scattering Studies of Nanostructures in Chemically Well-Defined Functional Polymers: Synthetic Polymers, Proteins, and DNAs

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Novel Brush Polymers as Biomaterials: Structure and Properties

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Probing Nanostructures of Functional Polymer and Copolymer Assemblies by Synchrotron Grazing Incidence X-Ray Scattering

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Quantitative Grazing Incidence X-Ray Scattering Studies of Nanostructures in Functional Polymers: Porous Polymers, Brush Polymers, Star Polymers, and Block Copolymers

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Self-Assembled Brush Polymers Bearing Zwitter-Ionic Sulfobetaine Moieties: Structures and Biocompabilities

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Synchrotron Grazing Incidence X-Ray Scattering Analysis of Functional Polymer Nanostructures

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X-ray and Neutron Reflectivity Study of Self-Assembled Brush Polymers Bearing Phosphocholine Moiety at the Bristle End

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