Stepwise assembly of enantiomeric poly(lactide)s on surfaces


Enantiomeric poly(lactide)s were assembled on a quartz crystal microbalance (QCM) substrate, which detects the mass of the polymers from the frequency shift, following immersion of QCM into alternating acetonitrile solutions. A quantitative QCM analysis at each step and a differential scanning calorimetric study of the assembly showed racemic crystal (stereocomplex) formation on the substrate surface. Atomic force microscopic observation showed a dotted nanostructure of the assembly. The assembly amount was increased with increasing the PLA concentration and the immersion time, while that was decreased with increasing the assembly temperature. The heterogeneous assembly was also prepared by altering the immersion time. We found that racemic crystal formation was applied to the alternate deposition of certain structurally regulated polymers.

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