Polymer-Induced Alignment of DL-Alanine Nanocrystals to Crystalline Mesostructures

摘要

Crystallization of DL-alanine by cooling of a supersaturated solution in the presence of a chiral double-hydrophilic block copolymer poly(ethy-lene glycol)-block-poly(ethylene imine)-S-isobutyric acid(PEG_(4700)-PEI_(1200)-S-iBAc)yields crystal superstructures with an astonishing morphology.Although analysis by light microscopy reveals these crystals to be apparently well facetted,electron microscopy shows that they consist of three-di-mensionally,well-aligned nanocrystals that are scaffolded to a so-called meso-crystal.This mesocrystal is formed by polymer-mediated structuration,and provides evidence for the importance of mesoscopic events in a typical crystallization process.