Chiral polymeric microspheres grafted with optically active helical polymer chains: a new class of materials for chiral recognition and chirally controlled release

A new class of chiral microspheres (μm in size) was prepared via suspension polymerization. The microspheres were constituted by optically active helical substituted polyacetylenes, which render the microspheres with considerable optical activity according to CD and UV-vis spectroscopy measurements. The chiral microspheres exhibited large oil-absorbency (ca. 70 g g−1 toward CHCl3). The presence of helical polymer chains enabled the microspheres to show remarkable chiral recognition and chiral adsorption ability: the maximum adsorption toward D- and L-menthol was 90 and 25 wt%, respectively. More interestingly, the microspheres also demonstrated remarkable chirally controlled release ability: under similar conditions, the release of L- and D-menthol was 95 and 65 wt%, respectively. The present chiral microspheres open new possibilities for developing materials used for enantiomeric drug release.