네마틱 액정의 찌그러짐에 의한 콜로이드 입자의 운동 연구

다국어 초록 (Multilingual Abstract)

First, we research the motions of spherical particle in non-uniform director field. The particles are immersed in nematic solvent. Two configurations exhibit when single particles with homeotropic boundary condition at the surfaces are located in the uniform director field. It is dipole and quardrupolar configuration. The dipole configuration accompanies a hyperbolic defect and the quardurpolar configuration is encircled by a Saturn-ring disclination ring at the equator of particle.
In this study, we construct a liquid crystal cell. By using a photo-alignment, we make a striped alignment pattern. The other structure has uniformly alignment. The two structures combine to a liquid crystal cell. Therefore, it is possible to make a pattern texture composed of the twisted and uniform domains. The boundaries of striped pattern induce a distortion of liquid crystal. When the single particle with hedgehog defect locates in a position of the twisted domain, it show a motion from one to the other boundary line. The particle of quadrupolar configuration shows little motions because of symmetric director field around particle. Therefore, the particle is interaction between distortion of liquid crystal and particle configuration.
Secondly, we have investigated the attractive interactions between two particles at boundary of striped pattern. The force of interaction induces the motion of particles. In this experiment, to determine a correlation of interactions between colloidal particles, we measure a velocity of particle. We use a logarithmic plot to check a power-low dependence of force. As a result, we confirm the coulomb-like elastic interactions of colloidal particles in a nematic liquid crystal.

목차 (Table of Contents)

• 1 서론
• 2 이론
• 2.1 액정 (Liquid crystals)
• 2.1.1 네마틱 액정 (Nematic liquid crystals)
• 2.2 액정의 배향
• 2.2.1 러빙법 (Rubbing method)
• 2.2.2 광배향법 (Photo-alignment method)
• 2.3 콜로이드
• 2.3.1 콜로이드 분산 (Colloidal dispersion)
• 2.3.2 네마틱 콜로이드 (Nematic colloids)
• 3 단일 입자의 운동
• 3.1 실험 방법
• 3.2 실험 결과 및 분석
• 4 두 입자의 운동
• 4.1 실험 결과
• 4.2 실험 분석
• 5 결론
• 6 참고문헌