Jae-Hong Choi

The six stilbene-based dyes containing benzoxazole substituents to improve solubility of dyes as well as the efficiency of fluorescence at blue emission were synthesized. In this work, absorption and fluorescent properties of the synthesized dyes were investigated. For the derivatization of benzoxazolyl stilbene dye, -NO₂ and -NH₂ groups were introduced in sequence onto benzoxazolyl rings. The emission maxima of the six dyes prepared were observed in the range of 435 nm~471 nm. In addition, the solubility of the dyes in dichloromethane was examined for application to the nonpolar polymer films such as PE, PP, PVC and so on. N-alkyl groups were determined to have a greater solubility of alkylated stilbene-based dyes than analogue containing and unsubstituted group. Furthermore, investigation of the optical effects of tortional strain according to conformation of side group was also performed. For identifying these properties, the geometry, dihedral angle, and other parameters of synthesized dyes were calculated by the density functional theory and time-dependent function using a gaussian 09 program.

Dyes are an important component of drop‐on‐demand ink‐jet inks and are commonly used in desktop printers. While they offer bright, vivid colour, these dyes exhibit poor light and water fastness. To combat this, researchers have started using pigmented ink‐jet inks instead of dye‐based inks to improve light and water fastness, but the pigments are insoluble in ink vehicles. To use pigments, dispersants must be applied; however, this is a delicate process because the properties of the dispersant substantially affect how the pigmented mill base must be prepared. In this study, polymeric dispersants are synthesised based on the properties and ratios of monomers and the molecular weights of polymers. In total, 14 types of polymeric dispersants are synthesised and examined, with special attention paid to the dispersing properties of particle size reduction and the stability of the pigmented mill base used to prepare drop‐on‐demand ink‐jet inks. This study describes the synthesis of the dispersants in terms of their suitability for commercial application.