Synergism of Carbon Nanotubes and Graphene Nanoplates in Improving Underwater Sound Absorption Stability under High Pressure

Abstract Underwater sound absorption materials with broadband and resistance to high pressure are crucial for noise control in the ocean. Herein a new method is presented to synergistically improve material's resistance to high pressure with broadband by hybridizing carbon nanotubes (CNTs) with graphene nanoplatelets (GNPs) in polydimethylsiloxane (PDMS) matrix. The micro‐structure shows the geometrical synergy between the nanoplatelets (GNPs) and nanotubes (MWCNT‐COOH). Besides, GNPs also form junctions with air micro‐voids. The underwater acoustic tests reveal that, compared with equivalent nanocomposites containing only CNTs or GNPs, the hybridized materials show significantly better sound absorption performance with a high hydrostatic pressure increased from 0.4 MPa to 1.0 MPa at the frequency range of 1500 Hz to 7000 Hz. Therefore, the hybridization of one‐dimensional (1D) and two‐dimensional (2D) nano‐carbon materials provides a new route for increasing the underwater sound absorption performance at high hydrostatic pressure.