Preparation of surfactant-free nanoparticles of methoxy poly(ethylene glycol)-b- poly (?-caprolactone-co-D, L-lactide) diblock copolymers)

Abstract

Surfactant-free nanoparticles of methoxy poly(ethylene glycol)-b-poly(ε-caprolactone-co-D,
L-lactide) diblock copolymers [MPEG-b-P(CL-co-DLL)] were prepared by modified-spontaneous
emulsification-solvent diffusion method. The diblock copolymers were synthesized by ring-opening
polymerization of CL and DLL using MPEG with molecular weight of 5,000 g/mol and stannous octoate as the
initiating system. Influences of CL:DLL ratios of the diblock copolymers on characteristics of the nanoparticles
were investigated and discussed. The sizes of colloidal nanoparticles from light - scattering analysis were in the
range of 84 - 639 nm. The nanoparticle sizes decreased with increasing the DLL ratio. Transmission electron
microscopy demonstrated that the almost nanoparticles have spherical shape with smooth surface.