Elastic deformation of multiwalled carbon nanotubes in electrospun MWCNTs-PEO and MWCNTs-PVA nanofibers

Polyethylene oxide (PEO) and polyvinyl alcohol (PVA) nanofibers (NFs) containing multiwalled carbon nanotubes (MWCNTs) have been prepared by electrospinning method. The elastic deformation of MWCNTs in these NFs, compared with the well-dispersed pristine MWCNTs, has been evaluated by statistically measuring the tortuosity change of MWCNTs, by adopting the tortuosity factor (TF) and calculating scale (CS) method. The average TFs of the well-dispersed MWCNTs increase nearly linearly with the increasing of CSs in the range of 30-500 nm. Comparatively, the TFs of MWCNTs in the PEO and PVA NFs first increase, then decrease with CSs and have an inflection point at the CS in 300 nm. The results indicate the elastic deformation of MWCNTs in electrospinning process, which is partly kept in the solidified MWCNTs-polymer NFs. The data comparison of MWCNTs-PEO and MWCNTs-PVA indicate that the polymers with relatively high elastic modulus can keep the elastic deformation of MWCNTs in relatively large degree. Finally, a simplified mechanical model is proposed to explain the interaction between MWCNTs and the polymer matrix. The calculated elastic modulus of the MWCNTs is in the order of magnitude of 100 GPa, in agreement with that of the AFM measurement.