抄録
Chitosan and its derivatives (CSDS) have been attractive as smart macromolecules in biomedical, biochemical and food sciences. The objective of this study was to investigate the effects of salts and ethanol on lower critical solution temperature (LCST) and particle formation in aqueous chitosan derivative (CSD) solutions, to interpret the phenomena thermodynamically and to show the potential to develop a novel particle formation process in an aqueous solution with changing temperature. The LCST was determined by measurement of percentile transmittance of the solution. It was found that the LCST was changed by salt type, salt concentration and CSD concentration. The LCST was decreased with the addition of salts at the high concentration of CSD. The particle size was also measured in various conditions by a dynamic light scattering. The particle formation occurred at a lower temperature with the addition of the salts. The particle size and distribution of the CSD were found to be significantly influenced by the addition of the salts. Furthermore, the above results were interpreted thermodynamically. The results obtained in this study were in good agreement with the phenomena found in an aqueous ethylene oxide-propylene oxide block copolymer (PPO-PEO) or PPO-PEO-PPO copolymer solutions. These findings are quite interesting and important to understand the process of particle formation, because the temperature of CSD particles formation appears to be shifted by changing concentration of salts, ethanol and CSD. Through the investigation, effect of various factor on LCST of CSD and its particle size were revealed and conditions of forming CSD particle was obtained.
