Design and characterization of controllable near-zero thermal expansion graphene rubber composites

In this paper, design and characterization of controllable near-zero thermal expansion graphene rubber composites are studied systematically. First, a novel design approach for near-zero thermal expansion materials is proposed, integrating centripetal-structured graphene aerogels (prepared via directional freezing to form radially aligned lamellae) with silicone rubber. Second, graphene rubber composites are prepared by combining silicone rubber with graphene aerogel through the surface attachment method, and the coefficient of thermal expansion of the resulting composite could be accurately controlled by precisely adjusting the mass ratio between the two components. Finally, the experimental results indicated that the axial coefficient of thermal expansion of the composite material within the temperature range of 20-100°C is as low as 3.1 × 10⁻⁷/°C, when the mass ratio of silicone rubber to graphene aerogel is set at 6:1, while the radial coefficient measures 8.9 × 10⁻⁶/°C, demonstrating near-zero expansion. The reversible compressive strain of this material reaches an impressive 99%; the maximum stress is 1.97 MPa, and its performance remains stable even after undergoing 200 cycles of compression. This study shows the composite material, with near-zero thermal expansion and excellent mechanical properties, is promising for precision engineering and intelligent devices.