재침전 방법을 이용한 Copper Phthalocyanine 나노입자 제조 및 유기 용매 내에 Copper Phthalocyanine의 분산 안정성 측정을 위한 새로운 연구방법

Abstract

Copper phthalocyanines (CuPc) is one of the significant organic pigments that is widely used in the commercial paint and ink industries. In recent years, they have become increasingly important in the high-technology industries such as electronics and reprographics, for example, the pigments used in color filters of liquid crystal displays. The dispersibility and the optical property of a pigment are prime considerations to the user in many industries. However, it is difficult to form a good and stable dispersion of CuPc. To increase the stability of CuPc dispersion, the important two processes in the manufacture of any pigmented system are needed to control the primary particle size and the dispersion of pigment. First, we studied the reprecipitation of phthalocyanines by pouring their sulfuric acid solutions into water for reduction of primary particle size and the controlled aggregation of pigment molecules generated from a soluble precursor in polymer and/or surfactant matrices. This method of crude β-CuPc transformed to α-CuPc and the particle size reduced to the nanoscale. Compared to the ionic surfactants, nonionic ones, polymer such as CTAB, SDS, Tween 20, PVP were found to prevent the growth of R-CuPc aggregates. Second, we studied the new method for direct and accurate analysis because the optical properties of organic pigments were determined markedly by the degree of dispersion. The new method of dispersion stability was analyzed by the extinction of UV spectra. The extinction spectra of various CuPcs in diluted nonaqueous medium (PGMEA) were measured and the extinction spectra change was analyzed for stability of the CuPc dispersions. Also, we control behavior of pigment using a dispersant (Ajisper PB-821) in organic medium (Propylene glycol monomethyl ether acetate) for an increase of the dispersion stability. The carboxylic groups of the dispersant improved a stability of CuPc dispersion. The stability of dispersion increased due to the extension of π-π interaction between the aromatic rings of the carbazole molecule and the π-electron of the carbonyl oxygen of the polymer. The nanostructures and morphologies of as-prepared CuPc materials were characterized by Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD). The sizes of the reprecipitated CuPcs in water were measured using a dynamic light scattering technique. Also, UV/vis spectrometer was used to analysis of dispersion stability and the dispersity of all CuPc samples in PGMEA was confirmed using a Optical Microscope (OM).