Study on the Friction Characteristics at the Imbibition Interface of Porous PDMS Sponge

This paper aims to clarify the interface friction characteristics of porous PDMS sponge under dry friction and imbibition conditions. The influence of multiple factors, including liquid viscosity, standing time, load, speed, and material properties on the interface friction characteristics of porous PDMS sponge was studied. It was found that the friction coefficient of the imbibition interface with low‐viscosity turpentine oil changed most significantly with the standing time, while silicone oil and L‐AN lubricating oil were basically unaffected. Moreover, the change in load had a significant impact on the friction coefficient of the dry friction interface, while the imbibition state was only sensitive to the change in load and speed when the liquid viscosity was 1000 cSt. At a 10:1 ratio, compared with dry friction, the viscous lag phenomenon at the interface in the imbibition state was significantly reduced. Based on the friction coefficient—displacement curve, the energy dissipation during the friction process was quantitatively analyzed, and the results were consistent with the friction coefficient trend. This study provides a theoretical basis for the interface tribology design and functional application of porous flexible materials for applications such as flexible sensors, wearable biomedical devices, and soft contact engineering systems.