Alternate Multilayer Films of Poly(vinyl alcohol) and Exfoliated Graphene Oxide Fabricated via a Facial Layer-by-Layer Assembly

Despite great recent progress with graphene-based materials, the development of strong and cost-efficient multifunctional graphene-filled polymer composites has not yet to be achieved. A key challenge in the fabrication of nanoplatelet-filled polymer composites is the ability to realize the nanometer-level dispersion and the planar orientation of nanosheets in polymer matrices. In this report, ultrathin multilayer (PVA/GO)n films were successfully fabricated by bottom-up layer-by-layer (LBL) assembly of poly(vinyl alcohol) (PVA) and exfoliated graphene oxide (GO), in which exfoliated GO nanosheets were used as the building blocks. Typical tapping-mode atomic force microscope (AFM) and field emission scanning electron microscope (FESEM) images demonstrate an ordered arrangement of organic and inorganic layers. A significant enhancement of mechanical properties has been achieved, that is, a 98.7% improvement of elastic modulus (Er) and a 240.4% increase of hardness. This may be attributed to the well-defined layered architecture with high degree of planar orientation and nanolevel assemblies of GO nanosheets in the polymer matrices.