As a maskless method, femtosecond (fs) laser micromachining has been used to fabricate microstructures on polymethyl methacrylate (PMMA) substrates, but the fs laser ablation promotes the formation of pores and redeposited debris, generating high surface roughness ranging from hundreds of nanometers to several micrometers. Herein, high-quality three-dimensional microstructures are prepared on PMMA surfaces by fs micromachining under suitable parameters followed by a short annealing treatment. Thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) and Raman spectra results reveal that a modified layer may exist on the laser-machined surfaces, which melts more rapidly during the annealing. Improved surface quality is probably caused by the micro-leveling effect of the modified layer. Laser processing parameters greatly affect the final surface morphology. Under optimal parameters, the surface microstructures prepared by this method have sharp edges and smooth inner walls with an average profile surface roughness of 45 ± 15 nm.

作为一种无掩模方法，飞秒 (fs) 激光微加工已被用于在聚甲基丙烯酸甲酯 (PMMA) 基板上制造微结构，但 fs 激光烧蚀促进了孔隙和再沉积碎片的形成，产生了从数百纳米到几纳米的高表面粗糙度微米。在此，通过在合适的参数下进行 fs 微机械加工，然后进行短暂的退火处理，在 PMMA 表面上制备了高质量的三维微结构。热重分析结合傅里叶变换红外分析 (TG-FTIR) 和拉曼光谱结果表明，激光加工表面可能存在改性层，在退火过程中熔化得更快。改进的表面质量可能是由改性层的微流平效应引起的。激光加工参数极大地影响最终的表面形态。在最佳参数下，该方法制备的表面微结构边缘锋利，内壁光滑，平均轮廓表面粗糙度为45±15 nm。