Fluid wetting infiltration characteristics and mechanical driving mechanism in rough rubber‐glass contact interface

Fluid wetting infiltration in rough rubber contact interface has a directly effect on mechanical lubrication and seal. To clarify its mechanism, contact property and fluid wetting infiltration process with time in rough rubber‐glass contact interface were obtained with an in situ observation instrument. The effect of wetting on the fluid infiltration area ratio at interface was analysed. Experimental results indicated that fluid wetting infiltration at interface was more tended to occur in high‐contact area ratio zone, and empty contact area was more likely to occur in low‐contact area ratio zone. Meanwhile, wetting had an obviously affected on fluid infiltration area ratio at interface. When contact angle of rubber‐liquid interface was 20°, the fluid could almost infiltrate the whole empty contact area of the interface. With the increase of contact angle of rubber‐liquid interface, the area of fluid infiltration was decreased. At last, liquid was completely excluded from the rough rubber‐glass contact interface as contact angle was bigger than 75°. Detailed research indicated that the fluid infiltration in the rough contact interface was the flowing of fluid in microchannels. The comparison of the capillary pressure with viscous drag force was the fundamental evaluation index for fluid infiltration at interface. In high‐contact area ratio zone, the size of microchannels was small, and the capillary pressure was more likely to overcome the viscous drag force of solid‐liquid interface. But in low‐contact area ratio zone, the situation was just the opposite. The microchannel size and surface tension of fluid were the effect factors of capillary pressure.