Nanometric Mechanical Behavior of Electrospun Membranes Loaded with Magnetic Nanoparticles

This work analyzes on nanoscale spatial domains the mechanical features of electrospun membranes of Polycaprolactone (PCL) loaded with Functionalized Magnetite Nanoparticles (FMNs) produced via an electrospinning process. Thermal and structural analyses demonstrate that FMNs affect the PCL crystallinity and its melting temperature. HarmoniX-Atomic Force Microscopy (H-AFM), a modality suitable to map the elastic modulus on nanometric domains of the sample surface, evidences that the FMNs affect the local mechanical properties of the membranes. The mechanical modulus increases when the tip reveals the magnetite nanoparticles. That allows accurate mapping of the FMNs distribution along the nanofibers mat through the analysis of a mechanical parameter. Local mechanical modulus values are also affected by the crystallinity degree of PCL influenced by the filler content. The crystallinity increases for a low filler percentage (<5 wt.%), while, higher magnetite amounts tend to hinder the crystallization of the polymer, which manifests a lower crystallinity. H-AFM analysis confirms this trend, showing that the distribution of local mechanical values is a function of the filler amount and crystallinity of the fibers hosting the filler. The bulk mechanical properties of the membranes, evaluated through tensile tests, are strictly related to the nanometric features of the complex nanocomposite system.

Automated summary

This research analyzes the mechanical properties of electrospun membranes of Polycaprolactone (PCL) loaded with Functionalized Magnetite Nanoparticles (FMNs) at nanoscale spatial domains. The study finds that FMNs have an impact on the crystallinity and melting temperature of PCL. HarmoniX-Atomic Force Microscopy (H-AFM) is used to map the elastic modulus on nanometric domains of the membrane surface, showing that the presence of FMNs affects the local mechanical properties. The distribution of mechanical values is influenced by the filler amount and crystallinity of the fibers hosting the filler, as confirmed by H-AFM analysis.