Quantitative nanomechanical mapping on poly(lactic acid)/poly(ε-caprolactone)/carbon nanotubes bionanocomposites using atomic force microscopy.

Poly(lactic acid)/poly(ε-caprolactone) (PLA/PCL) blends are among the most widely investigated biomaterials for tissue engineering scaffolds. Incorporating carboxylic multi-walled carbon nanotubes (MWCNTs) into the blend can further tune the microphase distribution and interface adhesion which conversely dominates the micromechanical properties. In this work, atomic force microscope (AFM) based quantitative nanomechanical measurements were applied on PLA/PCL/MWCNTs bionanocomposites for gaining knowledge at the nanoscale. Results show that MWCNTs are mainly dispersed in the PCL phase which is adjacent to the PLA phase. The microphase structures and the onsite microscopic Young's moduli distributions have significant changes with the introduction of MWCNTs. No obvious intermediate layer in the PLA/MWCNTs and PCL/MWCNTs interfaces is observed in the Young's moduli map, indicating weak interactions in the polymer/MWCNTs interface. Moreover, microscopic structure-property relationships of PLA/PCL/MWCNTs nanocomposites were discussed and correlated to the macroscopic mechanical properties. A better understanding of these properties would be helpful in tailoring the PLA/PCL based bionanomaterials for applications in tissue engineering scaffolds, where the nanomechanical information is critical. • The dispersion state of MWCNTs in PLA/PCL/MWCNTs composites was visualized by AFM. • The introduction of MWCNTs significantly affected the morphology of the nanocomposites. • New method nanomechanical mapping was presented to characterize the microscopic mechanical properties. • Microscopic Young's moduli distribution together with interface interactions of the nanocomposites was investigated. • The microscopic mechanical properties of the nanocomposites were related to their macroscopic mechanical properties. [ABSTRACT FROM AUTHOR]