Surface Properties of Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) Banded Spherulites Studied by Atomic Force Microscopy and Time-of-Flight Secondary Ion Mass Spectrometry

Banded spherulites of poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (P(3HB-3HV)) random copolymer were prepared by isothermal crystallization at 90 °C for 10 h. Using tapping-mode atomic force microscopy (AFM), the concentric periodic ridges and valleys on the surface of the banded spherulites of this polymer were found to consist of edge-on and flat-on lamellae, respectively. The periodic concentric ridges and valleys observed by AFM corresponded to the periodic extinction rings observed by polarized optical microscopy. AFM measurements showed that the interaction between the AFM probe and the sample surface can be significantly influenced by lamellar orientation.