Structure–Performance Correlation in PAN Nanofibers Reinforced With Carbon Nanotubes and Graphene Nanoplatelets

Electrospun mats have attracted growing interest due to their high surface area, mechanical flexibility, and tunable properties, making them promising for applications in wearable sensors, flexible electronics, and energy storage. This study investigates the incorporation of carbon‐based nanofillers into electrospun polyacrylonitrile (PAN) mats to enhance their electrical and thermal properties. Scanning electron microscopy (SEM) analysis showed that the nanofillers adhered to the surface of PAN fibers, with the addition of carbon nanotubes (CNTs) resulting in thicker fibers. In contrast, graphene nanoplatelets (GNPs) promoted the formation of finer ones. In hybrid systems, a synergistic effect was observed, reducing the average diameter of PAN/CNT fibers with the addition of GNPs. Fourier‐transform infrared spectroscopy (FT‐IR) confirmed the presence of the nitrile group characteristic of PAN and indicated structural changes due to interactions with the nanofillers. Differential scanning calorimetry (DSC) revealed a slight increase in glass transition temperature ( T g ), suggesting restricted chain mobility. Thermogravimetric analysis (TGA) showed that higher nanofiller content led to increased carbon yield, from 17.1% in neat PAN to 50.1% in the 2 wt% CNT/8 wt% GNP hybrid sample. Dielectric analysis indicated that CNTs significantly increased the relative permittivity ( ε r ), reaching 4.10 at 10 GHz for 2 wt% CNTs, compared to 2.25 for 10 wt% GNPs. Hybrid compositions performed best, with the 2 wt% CNT and 8 wt% GNP sample reaching ε r = 5.50. CNT‐reinforced mats exhibited pronounced anisotropy in dielectric response, especially when fibers were oriented parallel to the electromagnetic field, a behavior less evident in GNP and hybrid mats, indicating reduced filler alignment.