Formation Process of Core-Shell Microp articles by Solute Migration During Drying of Homogenous Composite Droplets
Nan Fu1,*（傅楠）, Winston Duo Wu1,*（吴铎）, Zhangxiong Wu1，Fei Tzhung Moo2, Meng Wai Woo2, Cordelia Selomulya2 and Xiao Dong Chen1
1Suzhou Key Laboratory of Green Chemical Engineering, School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou City, Jiangsu 215123, P.R. China
2 Dept. of Chemical Engineering, Monash University, 18 Alliance Lane, Clayton, VIC 3800, Australia
AIChEJ ,63:3297--3310,2017
Particle formation process during spray drying profoundly impacts particle morphology and microstructure. This study experimentally investigated the formation of core-shell-structured microparticles by one-step drying of composite droplets made of Eudragit® RS (a polycationic acrylic polymer in nanoparticle form) and silica sol. The formation of an incipient surface shell was monitored using single droplet drying technique, and the freshly formed shell was recovered for subsequent analyses. Adding silica to RS precursor increased the shell formation time and altered the properties of the incipient shell from water-dispersible to nondispersible. The incipient shell formed from RS/silica droplets with mass ratios of 1.5%:1.5% and 0.5%:2.5% showed ingredient segregation with a preferential accumulation of RS, similar to the shell region of dried microparticles. After shell formation, excess silica sol in the liquid phase could flow inward, producing a dense core. This mobility-governed solute migration would be useful for constructing core-shell microparticles using other precursor systems.
链接：http://onlinelibrary.wiley.com/doi/10.1002/aic.15713/abstract
