Conventional thermoplastic elastomer from rubber plastic blends has rubber domains of a few micrometers dispersed in a plastic matrix. Nanotailoring of novel thermoplastic elastomeric blends from polypropylene (PP) and fluoroelastomer (FKM) by a special green technique generated a unique morphology in which FKM was dispersed in the nanometer range (50-70 nm) into the continuous PP matrix. The evolution of the unique nanostructure morphology was explained with the help of a viscoelastic drop breakup mechanism. The nanostructured blends exhibited superior physical properties and outstanding oil swelling resistance and thermal stability, which increased upon vulcanization of the rubber phase in situ. For example, volume swell of nanostructured PP/FKM blends was 8-10% in ASTM oil #3 at 100 degrees C for 72 h, which was the lowest in this type of thermoplastic elastomer. Insights into how the unique morphology influenced the functional properties of thermoplastic elastomers was provided. These new thermoplastic elastomers can be used in the automotive industry, particularly as a liner material for car hoses where superior flexibility, oil resistance, and heat resistance are desirable properties.