Non-dewetting PTFE membrane

Related Documents

Non-dewetting PTFE Membrane Datasheet

Features

• Relatively high membrane surface energy（<30dyn）
• Wide temperature Range（-40°C - 260°C）
• Thickness（10-50μm）
• Resistant to strong acids, strong bases, and strong oxidants（eg.HNO3，H2SO4）
• Higher resistance to air pressure

Applications

• Strong acid and strong alkali filtration
• Solvent filtration in the semiconductor industry

Technical Parameters

FAQ

1.What is a PTFE membrane and what are its key characteristics?
PTFE (Polytetrafluoroethylene) membrane is made from expanded polytetrafluoroethylene (often referred to as ePTFE). It is renowned for its exceptional chemical stability and broad chemical compatibility, capable of withstanding nearly all strong acids, alkalis, and aggressive solvents. Additionally, PTFE membranes feature high thermal resistance and natural hydrophobicity, making them one of the most durable choices for both analytical laboratory and industrial filtration applications.

2.What is the difference between Hydrophobic and Hydrophilic PTFE membranes?

This is the most crucial distinction when selecting PTFE membranes:

Hydrophobic PTFE: This is the native state of the material. It repels water and prevents aqueous solutions from passing freely, but allows air, gases, and organic solvents to pass through.

Applications: Primarily used for gas filtration, sterile venting, and filtering strong organic solvents.

Hydrophilic PTFE: These membranes undergo a specialized surface treatment to become wettable by water. They permit the filtration of both aqueous solutions and organic solvents (or mixtures of both).

Applications: Widely employed in HPLC (High Performance Liquid Chromatography) sample preparation, particularly for the filtration of mobile phases comprising mixtures of water and organic solvents.

3.How does PTFE compare to PVDF or Nylon membranes?

Compared to Nylon or PVDF, PTFE's primary advantage lies in its exceptional chemical inertness. When handling highly corrosive solvents (such as concentrated acids or strong alkalis) or conducting extremely sensitive chemical analyses (demanding ultra-low extractables), PTFE is the optimal choice. Nylon may adsorb proteins, while PVDF, though chemically resistant, lacks the broad compatibility of PTFE.

4.Can PTFE membranes be used for sterile gas filtration or tank venting?

Yes, this is a key application for Hydrophobic PTFE. 
Because it can completely block liquid water and aerosols while allowing air to pass freely, it is commonly used for sterile air inlet of fermenters, tank vent filters, vacuum pump protection, and hydrophobic vent components in medical equipment. It can effectively retain bacteria and bacteriophages, achieving sterile filtration performance (typically using a 0.22 µm pore size).

5.Are our PTFE membranes reinforced with support materials?

Yes. Unsupported PTFE is naturally thin and flexible. To enhance mechanical strength and handling properties, we often provide PTFE membranes laminated with Polypropylene (PP) or Polyester (PET) support layers. This reinforcement ensures the membrane maintains integrity under high pressure or back-pulsing conditions.

6.Is the PTFE membrane autoclavable?

Yes. PTFE exhibits excellent thermal stability. It can withstand high-pressure steam sterilization at 121°C or 134°C. It is also compatible with Ethylene Oxide (EtO) sterilization, making it suitable for sterile pharmaceutical and biotechnology processes.

7.How do I pre-wet a Hydrophobic PTFE membrane for aqueous filtration?

If you only have a hydrophobic PTFE membrane but need to filter an aqueous solution, you must pre-wet the membrane with an alcohol (such as ethanol or isopropanol).

Wet the membrane with a small amount of ethanol.
Rinse off the ethanol with deionized water.
Filter the aqueous solution before the membrane dries.

Tip: For easier operation, we recommend directly using our hydrophilic PTFE membranes.

8.How is the protein adsorption rate of PTFE membranes?

PTFE has a certain level of protein adsorption. Although its adsorption is lower than that of nitrocellulose (NC) membranes, when handling valuable biological samples such as proteins or enzymes, PES (polyethersulfone) or CA (cellulose acetate) membranes are generally recommended if the goal is to recover proteins. However, if the purpose is to remove proteins or to filter highly corrosive biological reagents, PTFE is a safe choice.

9.What are the application cases for PTFE membranes produced by Membrane Solutions?

Membrane Solutions' PTFE membranes have been successfully deployed in the following areas:

Venting Applications

• Hydrophobic venting for electronic devices
• Hydrophobic/Oleophobic venting for automotive sensors
• Oleophobic venting for automotive engines
• Venting for high-end equipment heat dissipation
• Venting for food packaging
• Venting for lyophilization (freeze-drying)
• Venting for membrane distillation

Filtration Applications

• Sterile filtration
• Beer filtration
• Wine filtration
• Tea and beverage filtration
• Wastewater treatment filtration
• Centrifugal filtration
• Chemical solvent filtration
• Strong acid and strong alkali filtration

10.What are the current applications?

Mainly applied in the food, chemical, and biopharmaceutical industries, including plate membranes for wastewater treatment, membrane distillation, solvent filtration, concentrated sulfuric acid filtration, infusion set filtration, eye drop filtration, and centrifuge tube filtration.

11.What are the application cases of Membrane Solutions' PTFE membranes in biopharmaceuticals, and how are they used? Are they effective?

Membrane Solutions' hydrophilic PTFE membranes have been successfully applied in various filtration devices, 96-well plates, infusion sets (fluid-stop membranes), sterile filter cartridges, disinfectant water, hydrogen peroxide, and eye drop filtration. For sterile filtration, we generally recommend using membranes with a pore size of 0.22 µm or smaller.

12.What are the main performance differences between Membrane Solutions' PTFE membranes and those from other manufacturers?

Compared with PTFE membranes from other manufacturers, Membrane Solutions' PTFE membranes feature more comprehensive quality control, with membrane uniformity and performance differentiated through gradient screening to ensure relatively better batch-to-batch consistency. In addition, Membrane Solutions’ PFAS-free oleophobic venting membranes meet the latest regulatory testing standards, addressing concerns for users subject to regulatory restrictions.