Synthesis of amphiphilic polyaspartamide derivatives and construction of reverse micelles

Abstract

A series of amphiphilic graft copolymers based on biodegradable and biocompatible poly(aspartic acid)s were synthesized by a successive aminolysis reaction of polysuccinimide using octadecylamine/dodecylamine, and ethylenediamine-β-cyclodextrin/ethanediamine. The chemical structures of the copolymers were confirmed by FT-IR and ¹H NMR spectroscopy. Large compound reverse micelles consisting of numerous small reverse micelles with polar cores and hydrophobic shells were formed in octanol solution. The reverse micelles showed various particle sizes based on the different length of hydrophobic alkyl chains and molecular weight of polysuccinimide, as determined by dynamic light scattering. Interestingly, the particle size of micelles showed temperature dependence, the diameter decreased continuously with increasing temperature. Their morphology and assembly properties were characterized using scanning electron microscopy, transmission electron microscopy and fluorescence spectroscopy. The reverse micelles were extremely efficient in extracting Congo red from water into octanol, exhibiting a potential application as delivery vehicles in the pharmaceutical and cosmetic fields, and as nanocontainers for separation of inorganic molecules as well.