생체 고분자 키토산 기반의 다목적 응용 및 특성 분석

Abstract

Chapter 1. Mechanical properties and interfacial compatibility of functionalized carbon nanotubes as fillers for chitosan solid polymer electrolyte

The polymer solid electrolyte (SPE) has flexible and green characteristics, but has low ion conductivity. Plasticizers are added to SPE for increase of the ionic conductivity. Excessive addition of plasticizer to SPE expands and increases the amorphous region, reducing mechanical properties. Fillers are added to increase the reduced mechanical properties. The carbon nanotubes (CNT) have excellent mechanical strength and can be functionalized, it has the ability to chemically bond to a polymer matrix. However, the two capabilities of CNTs contradict each other. As the number of functional groups formed on the walls of CNTs to bond with the polymer matrix increases, the mechanical strength decreases. Conversely, when CNTs without functional groups are added to the polymer, the polymer solid electrolyte is easily damaged due to low interfacial compatibility. Therefore, it is necessary to find the appropriate range of two abilities to maximize the advantages of CNTs. this study aims to analyze the relationship between mechanical strength and interfacial suitability by controlling the number of functional groups formed in carbon nanotubes and adding them to SPE. in addition, plasticizers and dopants are added to improve the ionic conductivity of SPE. |Chapter 2. Control of porous structure thickness and pore size on based PDMS using eulsion and application of pressure sensor

A pressure sensor is a device that converts pressure into an electrical signal, and the type of pressure sensor is determined by various conditions such as measurement target, operating range, selectivity, stability, sensitivity, and response speed. Research is steadily being conducted to develop pressure sensors with a wider operating range, high sensitivity, and fast response speed. Among them, the frequency of applying a piezo-resistance type pressure sensor is increasing. In order to increase the sensitivity, a hierarchical structure such as a pattern or microstructure was applied to the surface of the pressure sensor to show higher sensitivity at the same pressure. Studies have been reported to form porous structures in patterns entered on surfaces to exhibit high sensitivity at very small pressures (<1,000 Pa). Very low sensitivity was confirmed at a relatively high pressure (>10 kPa). This is because when the pressure sensor is compressed by applying pressure, it tends to have saturation or low compressibility of the pattern and hierarchy applied to the surface. Conversely, the sponge-type pressure sensor appeared at high pressure, but there was a problem of low sensitivity at low pressure. In this study, porous structures were formed on the surface and inside to expand the operating range of pressure sensors and increase sensitivity. It is intended to develop a pressure-resistant pressure sensor that can expand the operating range and increase the sensitivity by adjusting the thickness of the porous structure formed inside and the size and amount of surface pores.