高分子纳米纤维表面压痕及其分形特征研究

采用静电纺丝法制备了纳米级高分子聚己酸内酯(PCL)纤维,通过扫描电子显微镜和原子力显微镜观察了聚己酸内酯纳米纤维的表面结构和微观特征,并通过原子力显微镜对纤维表面进行纳米压痕实验。实验发现随着压痕深度的变小,纤维的弹性模量呈现增大的趋势。利用统计分形理论对高分子纤维表面压痕过程进行建模,通过拟合实验曲线得到了材料的分形参数,该模型可以很好的模拟高分子纤维材料在纳米压痕实验中的尺寸效应。

Nanoindentation Tests and Research on the Fractal Characteristic of Polymer Nanofibers

Polymer nanofibers can be used as bio-scaffold in bioengineering.Electrospinning method was used to get polymer fibers in the nano scale,and the morphology and the microstructures of the fibers were characterized using the Scanning Electron Microscopy（SEM） and Atomic force microscopy（AFM）.The mechanical properties of the single fibers were characterized by AFM nanoindentation.The results showed that with the decreasing of the depth of the indentation,the Young＇s moduli of the fibers increased a lot.The microstrctures of the polymer materials can be described using Statistical Franctal,so fractal therory was used to model the nanoindentation tests of polymer fibers,which can well simulate the size effects in the nanoindentation tests,and also can be used to predict the mechanical properities of different polymer materials.