Polymer nanofibers have recently attracted significant interests in the heat transfer community,as they have been shown to become better thermal conductors when drawn into thin nanofibers.This was believed to be caused by reduction in internal structural defects which act as phonon scattering sites,thereby effectively increasing overall fiber crystallinity.It has also been shown that mechanical properties of polymer fibers are significantly altered from their bulk forms.In most cases,the Youngs modulus of nanofibers is found to be increased,while the mechanisms behind it are still elusive.Investigating the correlation between mechanical and thermal properties of polymer nanofibers would provide an opportunity to better understand both of the properties and elucidate the structure-property relationships.In this presentation,we will discuss our recent effort to experimentally characterize mechanical and thermal properties of semi-crystalline Nylon-11 nanofibers with diameter ranging from sub-100 nm to 500 nm.we will describe the instrumentations we developed that enable the characterization of these properties,including thermal conductivity,specific heat,and Youngs modulus,and then discuss and interpret the measurement results.