The authors propose a fast and novel method for the synthesis of polyaniline nanofibers and their incorporation into DI-water as a nanofluid. The thermal conductivities of the nanofluids are measured from 10 °C to 80 °C by using the transient plane source (TPS) method. The particle loading amount of nanofibers affected the thermal conductivity of the nanofluids. Scanning Electron Microscopy (SEM) was used to characterize the physical properties of the nanofibers....