Modification of medical-grade poly(L-lactide) using femtosecond laser filamentationWednesday (24.06.2020) 13:55 - 13:58 Room 1
We report filamentation-assisted laser modification of medical – grade bioresorbable poly(L-lactide) (PLLA) which is frequently used for bone and cardiovascular implants fabrication. The aim of the research was to determine the influence of spatial distribution of filamentary modifications on polymer properties. For this purpose we used TruMicro 2000 laser from Trumpf Laser GmbH. For current research we applied fundamental wavelength and shortest pulse of 270 fs. The pulse energy was adjusted in order to obtain possibly long single filamentary modifications caused by a single laser pulse. We fabricated three types of samples with filament spacing of 15, 30 and 50 µm in both directions. After modification samples were analysed by means of differential scanning calorimetry (DSC) that enables evaluation of thermal and crystallization behaviour of material. We present for the first time polymer thermal properties modification by generation of elongated microcavities using very fast method based on galvoscanner. Obtained microchannels have the length of 300 – 350 µm and diameter of around 1 µm. Filamentation tracks starts at the surface and ends close to the sample bottom. We discovered that filamentary modifications act as crystallization nuclei and cause increased ability of polymer to crystallize at lower temperature. The higher modification density the faster crystallization observed in DSC curves. This result is promising as a method of spatially selective modification and gradient properties writing. Drug insertion into the microcavities may be also possible.
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