Optical Transport Properties of Oriented Isotactic Polypropylene and Carbon Nanotube Nanocomposite Thin Films

ABSTRACTOptical transport through Isotactic Polypropylene (iPP) and multiwall carbon nanotubes (MWCNTs) nanocomposite thin films is important to many applications where optical transmission or polarization are used. Especially interesting is the case where the optical properties are anisotropic as in oriented thin films and the optical transport is different in the direction of orientation and perpendicular to it. Changing the orientation of the film or the polarization of the light can change the way in which the nanocomposite film interacts with light. Our polymer of choice, Isotactic Polypropylene, is one of the most widely used polymers which will increase the applicability of our results. We blended iPP with different concentration of carbon nanotubes (CNTs): 1%, 2% and 5% and oriented the thin film samples using melt-shear at 200°C and 1Hz in a Linkam microscope sharing hot stage. We measured that the index of refraction of the nanocomposites slightly decreased when CNTs are added and that when nanocomposites were shear-oriented at low loading of CNTs the index of refraction showed small difference in directions parallel and perpendicular to the direction of orientation. The extinction coefficient increased therefore it’s tuning in the nanocomposite films by the content of the carbon nanotubes can help devise new materials with the desired values of this property.