전기수력학적 젯 프린팅 기술을 이용한 실리카 기반 구조색 제작

Abstract

Structural coloration is a unique color due to periodic nanostructures. Periodic nanostructures have interference effects when light is incident, so that specific wavelengths are reinforced and the remaining wavelengths are canceled. This principle is based on bragg's law. bragg's law is a physics law for diffraction and reflection of light. When light is incident on a nanostructure with a certain pattern, a rainbow color appears. Nanostructured technology is essential to fabricate nanostructures with a uniform pattern, which is a processing technique for producing nanometer-sized patterns. There are many ways to fabricate periodic nanostructures, and the most popular technology in recent years is EHD Jet Printing. The principle of the EHD Jet Printing technology is to create a strong electric field between the nozzle and the substrate, and electrostatic force acts on the meniscus. This study proposes EHD Jet Printing technology for the production of structural coloration. Silica ink suitable for EHD Jet Printing was prepared, and silica nanoparticles were prepared by Stöber method. To verify whether the nanostructures produced by EHD Jet Printing expressed trucutral coloration, a control group was made to compare the optical properties. Stöber method was used to fabricate spherical silica nanoparticles. The size of spherical silica nanoparticles was controlled by varying the content of DI water. And ethylene glycol was used as a solvent to produce a silica ink suitable for EHD Jet Printing. Silica ink was produced in a ratio of 1:12 of ethylene glycol and spherical silica nanoparticles. Structural coloration was produced by simple drying and dip-coating as a control. In the simple drying method, the prepared silica ink was sprayed onto a glass slide, and then dried through a convecntion oven. In the dip-coating method, the glass slide was immersed in a beaker containing silica ink and then dried in a convection oven. The optical properties were attributed to the color change according to the size and angle of the silica nanoparticles. First, the size of silica nanoparticles was adjusted to 45 ml, 55 ml and 65 ml of DI water in the process of mixing DI water with EtOH. The color change according to the angle was photographed through the manufactured experimental equipment. The changed angle was increased from 0 ° to 10 ° and photographed from four angles.