Synthesis and self-assembly of stearic acid-poly (ethylene glycol) block copolymer

Stearic acid-poly(ethylene glycol) (STA-PEG) block copolymers with different hydrophilic segment length were successfully synthesized by the mild esterification. And self-assembly behaviour of the STA-PEGwas followed by fluorescence spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results show that the sphere micelles are formed with the STA block as the core and PEG block as the shell in aqueous solution. In addition, with the increase of PEG block length, the diameters of micelles increase from 148nm to 228nm, and the critical micelle concentration (CMC) decreased from 0.0013mg/ml to 0.0004mg/ml. The very low CMC value indicated that the STA-b-PEG can self-assemble into micelles easily and the formed micelles were stable in very dilute solution (paper)