• noble metals
• nanoparticles
• nanocomposite

The match between the functionality of nanoparticles and the processability of polymers is promising for the design of new optical, magnetic and sensor devices. The reinforcement of polymers using fillers, whether inorganic or organic, is common in modern plastics. Polymer nanocomposites or, with a more inclusive term, polymer nanostructured materials, represent a radical alternative to traditional filled polymer compositions. In contrast to ordinary polymer systems where reinforcement is on the order of microns, polymer nanocomposites are exemplified by discrete constituents on the order of a few nanometers with huge interfacial areas and confinement of polymer matrix chains at the nano-level: this enhance the properties of both components yielding to new applications in many fields. Another aspect to highlight is that functionality of nanonoparticles is “size dependent” and so the properties of final nanocomposites can be decided previously by fine-tuning the dimensions and the shape of the nanofillers.
The aim of this work was the dispersion in polymer matrices of noble metal nanostructured materials and the study of the optical features of the produced nanocomposites. The polymeric film nanocomposites containing AuNRs (gold nanorods), AuNPs (gold nanoparticles) and AgNPs (silver nanoparticles) were prepared by using a photochemical and a solvent-casting process both operating directly in the solid state and there were involved two different polymer matrices: Poly (vinyl alcohol) (PVA), a common thermoplastic matrix involved for many applications, and POLIDISP 7602, an industrial elastomer usually used in paint field.
In particular, uniaxial stretching of the nanocomposites can lead to an anisotropic distribution of the nanoparticles providing oriented films with polarization-dependent tunable optical properties. These dichroic properties are interesting as the films could find applications as colour polarizing filters, radiation responsive polymeric objects and smart flexible films in packaging applications.