How do the coefficients of friction differ between plastic types in wet conditions?

The coefficients of friction (COF) for plastics can vary significantly in wet conditions due to differences in material composition, surface texture, and hydrophobicity. Generally, plastics with smoother surfaces and hydrophobic properties, such as PTFE (Teflon), exhibit lower COF in wet environments because water acts as a lubricant. Conversely, rougher or hydrophilic plastics like nylon may retain higher friction due to water absorption and reduced slipperiness.

Experimental studies show that PTFE typically has a wet COF of 0.04–0.1, while polyethylene ranges from 0.1–0.3, and nylon can reach 0.2–0.5. Factors like temperature, contamination, and pressure further influence these values. Understanding these differences is crucial for applications like marine equipment, medical devices, and automotive components, where wet friction performance impacts safety and efficiency.

In summary, plastic selection for wet environments should prioritize low COF materials like PTFE for reduced wear and energy loss, while balancing other mechanical and chemical resistance needs.