Hybrid polymer–clay nanocomposites: A mechanical study on gels and multilayered films

The present contribution describes the preparation and characterization of polymer–clay nanocomposite gels and films containing poly(ethylene oxide) and various ratios of Laponite and Montmorillonite. The aim is to understand how clays with different chemistry, sizes and surface areas interact with each other and affect the structure and characteristics of polymer based nanocomposites in the form of both gels and multilayered films. The rheological behavior of the gels is compared to the spreading process during sample preparation and the resulting film structures and properties are analyzed. While gradually replacing Laponite clay with equivalent amounts of Montmorillonite clay decreases the viscosity of the resulting gels, we observed that the progressive increase of the Montmorillonite percent in the samples leads to a gradual increase of the storage and loss moduli in the multilayered films. At the nano-scale, SAXS and XRD measurements on films indicated that the clay platelets orient parallel to the film plane and that the polymer chains intercalate between silicate galleries. Thermal analysis shows that the polymer crystallinity can be controlled by combination and variation of different clays.