Intriguing morphology transformation due to the macromolecular rearrangement of poly(L-lactide)-block-poly(oxyethylene) : from core-shell nanoparticles to band structures via fragments of unimolecular size

摘要: Abstract We report on anomalous structural organization from core–shell nanoparticles of a hydrophobic/hydrophilic diblock copolymer consisting semi-crystalline poly( l -lactide) (PLLA) and poly(oxyethylene) (PEG). The was synthesized suspended in an aqueous medium to prepare its particles. resultant were spread germanium substrate trace the particle aggregation by atomic force microscopy (AFM) FT-IR spectroscopy. On surface, particles found change their shape into disks, with PLLA blocks being slightly crystallized. When heated 60°C, these disk-like aggregations burst small fragments then turned band structures. other hand, any ordered structure not observed when solution PLLA-PEG cast surface. In freeze-dried sample suspension, it that lamellar microphase-separated created crystallization annealing. lamella thickness analyzed small- wide-angle X-ray scatterings this reasonably correlated width structures formed It is therefore concluded formation regular can be guided both phase separation behaviors semicrystalline block chains PLLA-PEG.