신규 아민 기반 하이드로겔 입자의 제조와 그 응용에 관한 연구

Abstract

The colloidal phenomenon of responsive microgels is important due to the growing interest in a variety of systems such as sensors, drug delivery and rheological models. In order to understand the behavior of these complex systems, simpler model systems have been needed. Therefore, objective of this thesis is to develop mono-disperse micron-sized amine microgels for understanding the theoretical (e.g. mesh size) and experimental considerations from systematic analysis of pH-responsive phenomenon. This thesis is composed of six main chapters. In chapter 1, the general overview of responsive-microgel and the objective of this work are introduced. In chapter 2, thermodynamic factors of pH-responsive amine gel are considered based on the swelling theory. In addition, suitable equation for amine based microgel is derived to determine the mesh sizes. In chapters 3 and 4, poly(vinylamine) (PVAm) hollow particles are prepared because thin shell is easy to understand the relationships theoretical and experimental considerations. Chapter 3 presents a facile and straightforward method to synthesize uniform PVAm hydrogel hollow particles with excellent loading capability for active materials and controllable responsiveness by applying stimuli. The main purpose of chapter 4 is consideration of mesh sizes (pore sizes) of PVAm hollow particles and investigation of relationship between theoretical mesh sizes and permeability of macromolecules. Therefore, the pH-swellable PVAm hollow particles are prepared to adjust the mesh sizes. Based on the mesh sizes, the permeability of various molecular weight of dextran into PVAm hollow particles are investigated by adjusting the conditions of pH and ionic strength. And then, it is confirmed that estimated mesh sizes of PVAm hollow particles is well agreed with experimental data in permeability of FITC-dextrans. The purpose of chapter 5 is introducing the nano-particles into amine microgels based on the swelling behaviors to apply anode materials in lithium-ion batteries. Moreover, uniform sized PVAm particles are prepared instead of PVAm hollow particles to introduce the large amount of nano-particles. Therefore, the synthetic process of PVAm is modified and obtained PVAm particles are characterized in morphology, the degree of an amine moiety, swelling behaviors and mesh sizes. After employing the nano-particles into PVAm particles, calcination of these composite particles is carried out to apply the anode materials in lithium-ion batteries. In this case, enhanced cycling performance with superior capacity is showed than other literatures. In chapter 6, an electroless plating method is introduced for the coating of Cu onto the PVAm hollow particles using coordination bonding between Cu and amines. In this system, PVAm/Cu composite particles could be acquired by a relatively simple process in a short period of time by using a buffer solution. Moreover, the remarkable point is that PVAm/Cu composite particles have a flower-like morphology, which leads to high surface area. Therefore, this composite particle could be promising materials to provide the catalytic and electronics industry applications.