Submitted to NAMRC 36. Do not cite without written consent of authors. LASER SURFACE TREATMENT OF A BIODEGRADABLE POLYMER AT VARYING FLUENCES

For biodegradable polymers such as poly (Llactic acid) (PLLA), material crystallinity has a considerable effect on degradation and physical properties. In this work, the effects of laser fluence of a 355 nm UV Q-switched Nd-YAG laser on the crystallinity and conformation at the surface of PLLA films and the factors affecting the transformation are investigated. Electron microscopy, X-ray diffraction and Infrared spectroscopy are used to study the effects at varying fluences. The melting and crystallization kinetics of PLLA are examined to understand the important parameters that determine the overall crystallinity. Potentially, laser surface treatment at varying fluences can be used to spatially control the generation of a polymer surface with an altered degree of crystallinity. Such a structure may have applications including time released drug delivery.