RESUMEN
Hexagonal boron nitride has displayed increased potential in heat dissipation applications due to its desirable high thermal conductivity and remarkable thermal stability. However, the large-yield and high-quality preparation of boron nitride nanosheets (BNNSs) has been still an enormous challenge. In present work, we developed a universal exfoliation strategy to synthesize few-layer and defect-free BNNSs, which involved the intercalation of hexafluorosilicates/sodium hydroxide into BN crystals followed by exfoliation through a mild stirring process. The yield and concentration of as-obtained BNNS reached up to 78.5% and 12.78 mg/mL, respectively. More importantly, this method has been proven to exfoliate other layered materials like graphene (G), MoS2, and WS2. These as-obtained BNNSs can be directly used for constructing freestanding papers with high thermal conductivities. Typically, the thermal conductivities of the BNNS-G hybrid paper were up to 63.5 W/mK along the in-plane direction and 7.4 W/mK along the through-plane direction. According to the thermal interface materials performance measures, BNNS-G hybrid paper shows great promising applications for heat transfer in integrated circuit packaging.
RESUMEN
Graphene shows great promise for advanced filtration membranes with high permeance and enhanced rejection. Here we demonstrate filtration membranes with a nanochannel network for superior separation performance using 100-500 nm-wide graphene nanoplatelets (GnPs) that are efficiently prepared via a green method. The resulting membranes exhibit a well packed layer structure formed by GnPs and are highly stable in water and organic solvents and even in strongly acidic and alkaline media. Moreover, the GnP membranes possess high fluxes and good selectivity in both water and organic solvents based on the small size nanoplatelets and the stable nanochannels between the GnPs. The exfoliated GnPs and the subsequent membranes show great potential for practical applications in water purification and organic solvent filtration.