writer：Liyang Jia, Jihai Zhang, Gehong Su, Zhuo Zheng, and Tao Zhou*
keywords：laser foaming, near-infrared pulsed laser, polymer, multi-layer graphene, laser writing
source：期刊
Issue time：2020年
Our study proposed an efficient and environment-friendly strategy to realize the locally controllable surface foaming on polymers via near-infrared pulsed laser. This laser foaming was induced by the multi-layer graphene (MLG), and only 0.05 wt.% MLG gave the polymer an excellent foaming performance with good smoothness and a foaming height of 0.41 mm. Benefited from programming and automatically controlling of the laser system, foamed patterns of arbitrary shapes with 3D appearance could be accurately written on the polymer surface. SEM confirmed that the uniform cells produced by laser foaming were mainly ellipsoidal with closed-cell structures (D=31.5 μm); moreover, the surface foam had three layers with a total thickness of 633.7 μm. XPS revealed the surface carbonization of the foam during laser foaming. Both ATR-FTIR and XPS confirmed the weak oxidation of the PP matrix caused by laser due to the appearance of C?O and C=O groups on foams. Besides, the Raman depth imaging demonstrated the layered carbonization distribution in the foam surface. The micro-Raman spectroscopy confirmed that the amorphous carbon and the sp/sp2 carbon (C≡C/C=C) were two main carbonized products of PP. This study also proposed the mechanism of polymer laser foaming induced by MLG.