Synthesis and characterization of crown ether containing poly(L-lactide)s

The combination of macromols. and metal contg. units can lead to novel supramol. architectures with interesting new phys. and mech. properties. Here, we report on our investigations concerning the utilization of a functionalized crown-ether as initiator for the controlled ring-opening-polymn. of L-lactide. Both 1H-NMR spectroscopy and GPC demonstrated the incorporation of the crown ether into the polymer chains. Moreover, AFM investigations showed the formation of nanoporous films by spin coating of a soln. of the polymeric crown ether in tertrahydrofuran satd. with potassium iodide. Upon annealing, this nanoporous structure was transformed into a cryst. film, whereby layers with a thickness that corresponds to the length of a single polymeric arm of the poly(L-lactide) crown ether were found. Although, the nanoporous films could be reproducibly formed by spin coating the polymeric crown ether, the mechanism and the driving force for this behavior are not yet understood