초록

첫째로, 제한공간에 존재하는 콜로이드입자에 대한 농도분포와 확산현상에 있어 입자의 농도와 상호작용의 영향에 대해 모사하였다. 구형 입자는 물론이고, 축대칭(axisymmetric) 구조를 갖는 비구형(non-spherical) 입자에서 나타나는 배향(orientation) 효과도 다루었다. 둘째로, 유연한 사슬구조를 갖는 고분자전해질(polyelectrolyte)에 대한 연구로서 농도분포와 형태(conformation) 거동에 대한 해석적 결과와 진한 농도에 대한 혼성(hybrid) 분자모델링 방법의 기본적인 적용을 다루었다.

Abstract ▼

Even though purely steric partitioning within well-defined pores was treated, analytical approximations based on perturbed approach have been proved to be unreliable predictions of concentrated colloids for the whole range of relative pore size from wide to narrow. Concentration profiles of spherica

Even though purely steric partitioning within well-defined pores was treated, analytical approximations based on perturbed approach have been proved to be unreliable predictions of concentrated colloids for the whole range of relative pore size from wide to narrow. Concentration profiles of spherical colloids both in a cylindrical pore and in a bulk are obtained for a wide range of solute concentrations by employing the Gibbs ensemble Monte Carlo scheme, in which two kinds of stochastic perturbations are performed with a random displacement of solutes and random interchanges of solutes. The hydrodynamic coefficient for diffusive hindrance factor applied in this study is the earlier provided result using an centerline approximation technique. The long-range electrostatic interactions between the particle and the adjacent wall and between the particles are determined by solving with the singularity method, which provides accurate solutions to the linearized Poisson-Boltzmann equation.The obtained concentration profiles indicate that, whether both solutes and pores are uncharged or of like charge, solute-solute interactions promote concentration buildup near the pore wall. Remarkably, our simulations reveal a possible occurrence of physical adsorption inside narrow pores, of which the partition coefficient exceeds one in the system of charged solutes and uncharged pore wall with higher solute concentration. Due to the interplay of solute-solute and solute-wall interactions associated with repulsive energy, the hindered diffusion coefficient of charged system is predicted to increase with increasing solute concentration or ionic strength of solution, for a given relative pore size. It is known both the solute concentration and the solution ionic strength considerably affects on the hindered diffusion, although very little experimental data is available.The GEMC simulation has also been performed to estimate concentration partitioning for axisymmetric non-spherical colloids in various aspect ratios as well as solute concentrations. The orientation effect results in the enhanced concentration partitioning with increasing solute concentration, compared to the case of spherical colloids. A theoretical investigation on the behavior of a uniformly-charged polyelectrolyte confined in a charged cylindrical pore has been conducted. On the basis of the first order perturbation theory and the variational theory, predictions on the partition coefficient and the associated chain conformations are made in a variety of situations. By employing the effective step-length description, the intramolecular interactions between pairs of monomers are found to be as much important as the direct polymer-pore interaction in determining the concentration partitioning behavior. Depending upon the ionic strength of the embedding electrolyte solution, the polyelectrolyte conformation gets stretched or follows self-avoiding walk, yielding a significant reduction in the partitioning compared to the ideal chain result. Effects of the repulsive or attractive polymer-pore interactions are also examined, which accompany localized monomer density distributions near the pore axis or near the pore wall, in respect.The understanding of polyelectrolytes needs more complex knowledges due to the coupling between long-range interactions and the innate nature of polymeric molecules, in which new length scales as well as new degrees of freedom are introduced. Essentially, molecular modeling and simulation allow to examine this system. The hybrid methods combining Monte Carlo (MC) and molecular dynamics (MD) are used to look at both the conformational change and the density profile of charged polyelectrolytes. Simulation results on the chain conformation can be observed by providing the visualizations.

목차 Contents

• 제1장. 서론...13
• 제2장. 국내외 기술개발 현황...14
• 제1절. 국내외 비교분석...14
• 제2절. 구체적인 현황...15
• 1. 분자모델링 연구 측면...15
• 2. 선진외국의 소프트웨어 개발 현황...17
• 제3장. 연구개발수행 내용 및 결과...20
• 제1절. 제한공간에서 콜로이드 입자의 농도분포와 제한확산...20
• 1. 연구배경...20
• 2. 깁스앙상블 몬테카를로(Gibbs ensemble Monte Carlo)법...24
• 3. 정전기적 상호작용의 해석...28
• 4. 상호작용에너지(interaction energy) 계산...30
• 5. 전산모사수행 및 결과...32
• 6. 비구형(non-spherical) 입자에 대한 해석...50
• 가. 무한히 묽은(infinite dilute)경우...50
• 나. 진한 농도의 경우...52
• 7. 결론...58
• 사용기호...59
• 제2절. 고분자 사슬에 대한 해석 및 시뮬레이션...61
• 1. 제한공간에서 하전된 고분자의 농도 분배와 형태(conformation)에 대한 해석...61
• 가. 기본개념...61
• 나. 분배계수(partition coefficient)의 정의...61
• 다. 비하전 고분자의 분배계수...63
• 라. 기공과 고분자사이의 전기적 상호작용의 효과...67
• 마. 결론...73
• 2. 고분자전해질 용액에 대한 혼성(hybrid) 분자시뮬레이션...83
• 가. 밀도분포(density profile)...83
• 나. 사슬형태(chain conformation)...84
• 제4장. 연구개발목표 달성도 및 대외기여도...90
• 제5장. 연구개발결과의 활용계획...91
• 제6장. 참고문헌...93