Choosing the Right Membrane for Silicone Oil Repellency

Silicone oil is commonly used in various industries, including automotive, cosmetics, and medical devices, due to its lubricating, insulating, and water-repellent properties. When selecting a membrane for applications involving silicone oil, it’s crucial to consider the material's ability to repel the oil effectively while allowing air to vent through. Silicone oil, with a surface tension ranging between 17-22 dynes/cm, can be challenging to manage, as certain membranes may allow the oil to penetrate and pass through their pores.

Oleophobic membranes are designed to resist the penetration of oils, making them ideal for applications where oil repellency is required, such as in filtration and venting systems. However, in some cases, even membranes with oleophobic properties, like some grades of the PTFE Aspire laminated membrane, can experience issues when exposed to silicone oil. Despite being engineered to repel oils, the silicone oil can wet out and permeate the membrane rapidly during testing.

To address this problem, we recommend using an oleophobic membrane with a high AATCC grade—specifically, a membrane with a grade of at least 3. This grade indicates the membrane's ability to repel substances with specific surface tensions:

  • Grade 1: Repels n-heptane (20.1 dynes/cm)
  • Grade 2: Repels n-octane (21.8 dynes/cm)
  • Grade 3: Repels n-decane (23.5 dynes/cm)
  • Grade 4: Repels n-dodecane (24.0 dynes/cm)
  • Grade 5: Repels n-tetradecane (25.0 dynes/cm)
  • Grade 6: Repels n-hexadecane (27.3 dynes/cm)
  • Grade 7: Repels n-octadecane (27.8 dynes/cm)
  • Grade 8: Repels n-eicosane (30.6 dynes/cm)

Given the surface tension of silicone oil, a membrane with at least a Grade 3 rating is necessary to prevent the oil from wetting out and penetrating the membrane. This ensures that the membrane can effectively vent air while keeping silicone oil at bay.

By choosing the appropriate membrane with a higher AATCC grade, you can ensure optimal performance in applications requiring the separation of air from silicone oil, thereby avoiding any potential issues with oil permeation.

For further assistance in selecting the right membrane for your specific needs, please contact our team of experts.