A new strategy for air-stable black phosphorus reinforced PVA nanocomposites

Black phosphorus (BP) has attracted extensive scientific interest due to its particularly unique electrical properties. In recent years, an increasing number of researchers have shown great interest in the electrical and optical performance of BP in practical applications. However, the exploration of its mechanical properties is rare because BP tends to be oxidized in the atmosphere. In this study, BP nanosheets as two-dimensional nanofillers were used to reinforce the poly(vinyl alcohol) (PVA) matrix. The resultant BP-PVA nanocomposites presented excellent air-stability due to the formation of saturated P-O bonds outside the PVA-coated BP nanosheets. In addition, friction between the BP nanosheets and the PVA matrix led to increased strength, toughness, and modulus, which was confirmed by Raman spectrum analysis. The maximum tensile strength is up to 316.9 ± 12.1 MPa, which is 1.9-times higher than that of a pure PVA film. This strengthening effect of BP in the PVA matrix is superior to that of graphene reinforced PVA nanocomposites with similar content of graphene, indicating a favorite mechanical increase of BP in nanocomposites.