Laser and Fiber Electronics Group, Faculty of Electronics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
Department of Engineering and Technology of Polymers, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
Sci Rep. 2019 Feb 28;9(1):3069. doi: 10.1038/s41598-019-39640-1.
Over the past few years we have witnessed growing interest in ultrafast laser micromachining of bioresorbable polymers for fabrication of medical implants and surface modification. In this paper we show that surface structuring of poly(L-lactide) with 300 fs laser pulses at 515 and 1030 nm wavelength leads to formation of defects inside the polymer as a result of laser beam filamentation. Filament-induced channels have diameter around 1 μm and length of hundreds of micrometers. SEM images of microchannels cross-sections are presented. The influence of wavelength and pulse spacing on bulk modification extent was investigated and parameters limiting filamentation were determined. We show that filamentation can be used for controlling properties of PLLA. The presence of filament-induced modifications such as empty microchannels and pressure wave-induced stress lead to increased ability of polymer to crystallize at lower temperature. Crystallization behaviour and crystal morphology after laser treatment was investigated in details using different analytical techniques such as WAXD, DSC and FTIR/ATR. Hydrolytic degradation experiment was performed. Presented method can be applied for controllable, spatially distributed modification of polymer crystallinity, crystalline phase structure and hydrolytic degradation profile.
在过去的几年中，我们见证了人们对用于制造医疗植入物和表面改性的生物可吸收聚合物的超快激光微加工越来越感兴趣。在本文中，我们表明，使用 515nm 和 1030nm 波长的 300fs 激光脉冲对聚（L-丙交酯）进行表面结构化，会导致聚合物内部形成缺陷，这是由于激光束细丝化所致。细丝诱导的通道直径约为 1μm，长度为数百微米。给出了微通道横截面的 SEM 图像。研究了波长和脉冲间距对体改性程度的影响，并确定了限制细丝化的参数。我们表明，细丝化可用于控制 PLLA 的性能。存在细丝诱导的改性，例如空微通道和压力波诱导的应力，导致聚合物在较低温度下结晶的能力增强。使用不同的分析技术，例如 WAXD、DSC 和 FTIR/ATR，详细研究了激光处理后的结晶行为和晶体形态。进行了水解降解实验。所提出的方法可用于可控的、空间分布的聚合物结晶度、晶体相结构和水解降解谱的改性。
