Biomimetic polydimethylsiloxane (PDMS)/carbon fiber lamellar adhesive composite in thermal vacuum environment

Abstract In this paper, the adhesion properties of polydimethylsiloxane (PDMS)/carbon fiber composites in a thermal vacuum environment were obtained by a self-made adhesion test platform. Ladybird-biomimetic PDMS/carbon fiber lamellar composite imitated the gradient stiffness structure of ladybird setae. The influences on the adhesive material properties were investigated, including the mass-ratio of base and curing-agent, ambient pressure and temperature. The results showed that when the mass-ratio of base and curing-agent of the upper PDMS layer was set to 30, the normal average adhesion could reach 3.8 N cm-2 and 5.4 N cm-2 under vacuum and atmospheric pressure respectively, and the material had better surface adaptability. Due to negative pressure, the normal adhesion under atmospheric pressure was generally better than that in a vacuum. Both in atmospheric and vacuum environments, the normal adhesion remained basically around the initial value after more than 260 cyclic tests. High temperature reduced the adhesion properties of the materials. Combined with thermogravimetric analysis (TGA) results and the material compliance data, the reasons for the adhesive properties changing were given. This work introduces a method to improve the adaptability of adhesive materials, and provides an important basis for the application of PDMS/carbon fiber lamellar composites in space and other thermal vacuum environments.