Crystal growth in poly(L-lactide) thin film revealed by in situ atomic force microscopy

Direct visualization of crystal growth in poly(L-lactide) thin films was carried out by using a temperature-controlled atomic force microscopy (AFM). At the initial stage of crystallization, edge-on lamellar crystals have nucleated and elongated. Subsequently, the edge-on lamellar crystals showed S-shaped morphology and changed their orientation from edge-on manner to flat-on one. The curvature of edge-on lamellar crystal has been discussed in terms of inclination and distortion of polymer chains in the crystal. In addition, mechanism on the formation of flat-on crystal from edge-on lamellae was proposed as derivative growth on the basis of in situ AFM observation of crystal growth and enzymatic degradation.