| Polyaniline?PANI?is one of the new research hotspots concerning conductive polymers,owing to its specific structure and conductivity induced by doping acid.Polyaniline is a conducting polymer with incredible promise,but it has had limited use due to poor reaction control and processability.Polyaniline nanofibers,on the other hand,have demonstrated,through manufacturing techniques discovered during the past decade,increased processability,higher surface area,and improved consistency and stability in aqueous dispersions,The electrospun PANI nanofibers have high surface-to-volume ratio and high surface energy.However,it is difficult to fabricate continuous pristine PANI nanofibers.Therefore,various polymers have been investigated for the fabrication of composite electrospun materials.In this work,PANI doped poly??-caprolactone?/poly?lactid acid??PCL/PLA?nanofibrous membranes were fabricated.The morphology and structure of the nanofibrous composites were examined using scanning electron microscope?SEM?,infrared spectrum?FT-IR?,differential scanning calorimeter?DSC?,and X-ray photoelectron spectroscopy?XPS?.The results showed that the average fiber diameter decreases with the decreasing polymer concentration,and increasing electrospinning voltage,as well as the incorporation of PANI into the blend nanofibers.The average fiber diameter decreased from 782 nm for PCL/PLA nanofiber to 346 nm with the PANI doping concentration of 3%.Meanwhile,the pore number on the fiber surface increased with the increasing environmental humidity.The result of DSC exhibited the melting peak and cold crystallization peak of PLA,as well as melting peak and crystallization peak of PCL,while the crystallization peak of PLA is not obvious.The result of XPS demonstrated that the PANI is in the emeraldine oxidation state.Furthermore,the PANI coated core-sheath structural PCL/PLA nanofibers were fabricated by in-situ polymerization.The effect of polymerization conditions?i.e.reaction time,amount of aniline content,and plasma pretreatment?on the PANI coating were investigated.The morphology and composition of blend fibers were examined by SEM,FT-IR,and XPS.The results showed that the coating of PANI on the fiber surface was enhanced with the reaction time.The PANI shell was uniformly coated on the fiber surface after plasma treatment and enhanced the wettability of the membranes.The conductivity was 1.18×10-3 S/cm with the polymerization reaction time of 2 h.MTT assay demonstrated that the composite membranes have good biocompatibility.In order to investigate the influence of MWCNTs on the conductivity and morphology of the nanofibers,MWCNTs/PANI/PCL/PLA nanofibrous scaffolds were fabricated.The grooved morphology on the fiber surface decreased with increasing concentration of MWCNTs.The water contact angle was the lowest when the concentration of doped 2%MWCNTs.The conductivity increased from 1.40×10-5 S/cm for PANI/PCL nanofibrous membranes to2.32×10-5 S/cm for 2%MWCNTs/PANI/PCL/PLA nanofibrous membranes.Moreover,the MWCNTs/PANI/PCL/PLA composite scaffolds did not exhibit an obvious toxicity on cells.Cell number increased gradually with the increase of incubation time,however,no obvious difference of cell proliferation was observed among MWCNTs composite nanofibrous membranes. |
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