Nanoscale Surface Patterns from 103 Single Molecule Helices of Biodegradable Poly(l-lactic acid)

Atomic force microscopy, reflection absorption infrared spectroscopy, and X-ray reflectivity studies reveal that poly(l-lactic acid) molecules in Langmuir−Blodgett (LB) films exist as 103 helices over nearly the entire length of the polymer chain. This feature gives rise to LB films with highly ordered nanoscale smectic liquid crystalline-like surface patterns with low surface roughness and lamellar spacings that scale with molar mass. These studies provide a new approach for controlling surface morphology with a biodegradable polymer commonly used for drug delivery and tissue engineering.