Selective localization of carbon nanotubes at the interface of Poly(L-lactide)/Ethylene-co-vinyl Acetate resulting in lowered electrical resistivity

The ternary composites of Poly(L-lactide)/Ethylene-co-vinyl Acetate (PLLA/EVA, 60/40) containing different concentrations (0.5–3.0 wt%) of carbon nanotubes (CNT) were prepared through the master batches of the CNT/PLLA and the CNT/EVA, respectively. Through the joint action of the thermodynamic factors, which determine the degree of the migration between the two phases of an immiscible polymer blend or the selective localization of the CNTs in a specific phase, and the kinetic parameters which determine the migration rate from one phase to the other phase during the processing, CNTs were stabilized at the EVA side of the interface of the PLLA/EVA blend with a co-continuous structure when the composites were prepared from the master batch of the CNT/PLLA. Measurements showed that at a certain CNT concentration, the electrical resistivity resulting from the localization of the CNTs at the EVA side of the interface was much lower than that resulting from the selective localization of the CNTs in the EVA phase. Another exciting aspect of this research was that in the PLLA/EVA blend, viscosity ratio was proved to be more decisive in determining the selective localization of the CNTs than interfacial energy.