Visualizing the selective localization of carbon nanotubes in immiscible polymer blends

Abstract This paper examines the migration mechanisms of multiwalled carbon nanotubes (MWCNTs) in 80/20 polyvinylidenefloride/polystyrene (PVDF/PS) and 80/20 polyvinylidenefloride /polycaprolactone (PVDF/PCL) blends. We contrasted the migration of MWCNTs in a low‐viscosity, semi‐crystalline PCL phase versus that in a high‐viscosity, amorphous PS phase. With a 1 vol% loading of MWCNTs, the PVDF/PCL system required 54% higher processing work relative to the neat blend, while the PVDF/PS system required 360% higher work. A visualization system was used to capture the changes in the structure of the blend throughout the mixing process. The structural changes in the blend were correlated with the processing Work and the morphology through electron microscopy. Using the Young equation, for the PVDF/PCL blend, MWCNT is predicted to have a thermodynamic affinity to migrate to the interface, while preferring to remain in the PVDF phase for the PVDF/PS system. However, in practice, for the PVDF/PCL system, the MWCNTs are localized in the PCL phase, while the MWCNTs remained scattered between the PS and PVDF phases for the PVDF/PS system. The viscoelastic properties of the polymers, specifically the viscosity of the minor component, played a crucial role in the migration mechanism. Due to a better dispersion of MWCNTs, the rheological and electromagnetic properties of the PVDF/PCL system are significantly higher. Highlights In‐situ visualization of carbon nanotubes migration during blending. Examining the influence of viscosity of the blend on the migration of nanofiller. Correlating the torque of mixing to the morphology of blends.