Preparation of ultra-high thermal conductivity and excellent flame retardant MXene/f-PS nanocomposite film by a simple electrostatic self-assembly approach

Polystyrene (PS) nanospheres are non-covalently modified by PDDA, and a series of flexible nanocomposite films are fabricated with MXene nanosheets through electrostatic self-assembly and further hot-pressing. Due to the strong surface reactivity and the large specific surface area of the f-PS nanospheres, they are completely encapsulated by MXene nanosheets by serval interaction forces. This prevents the MXene nanosheet defect of easily stacked and agglomerated and maximizes the high thermal conductivity of MXene. SEM characterization verifies that a compact and long-range ordered thermal conductive path is formed in the microstructure of the nanocomposite film, as well as effectively improves interface compatibility, and reduces the generation of interfacial thermal resistance. At the same time, combined with the morphology results of the prepared nanostructures, the effects on thermal conductivity, flame retardant properties and mechanical properties are analyzed in detail. When the amount of filler is 90 wt%, the in-plane thermal conductivity increases dramatically to 40.39 W m −1  K −1 , which is 74.8 times that of f-PS. What's more, the 90M/f-PS nanocomposite film exhibited satisfactory flame retardancy and thermostability, decreasing the PHRR from 300 to 58 W g −1 and 70.0 wt% residue. This study provides a facile route for the design of thermal management interface materials with high thermal conductivity and flame retardant properties.