1.What is a PTFE Membrane?

Polytetrafluoroethylene (PTFE) membrane filter is made of polytetrafluoroethylene, which is expanded and stretched to form a microporous membrane. 
It's available in hydrophilic, hydrophobic, unlaminated, and laminated options for a wide range of applications and temperatures.
Polytetrafluoroethylene (PTFE) membranes are resistant to high temperatures, strong acids, strong alkalis, organic solvents, and oxidants. It is chemically compatible and resistant to most chemical solvents and chemically stable and inert, suitable for chemically corrosive organic solvents, aqueous solutions, and gases, and has resistance to most acids, alkalis, and solutions.

2.What is the difference between hydrohobic and Hydrophlic ?

The polytetrafluoroethylene (PTFE) membrane is an inlet membrane, a hydrophobic membrane filter, which is treated with ethanol or isopropanol to become a hydrophilic membrane filter.
The hydrophobic nature of PTFE promises its long-lasting unwetted status even be kept contacting with water or other normal liquids, and the open porous structure provides a wide range of pore size, 0.02μm to 10μm, ensuring the retention of bacteria, virus, and particles is always effective while maintaining the excellent gas permeability.
Naturally hydrophobic; they are very useful for aerosol sampling, air venting, and gas filtration, especially in environments also containing water vapor. 
Hydrophilic PTFE membrane is made of pure PTFE membrane bonded to a polypropylene non-woven support. The extreme chemical compatibility makes it an ideal material for filtration of almost all solvent, acids and alkaline solutions, and organic-based aqueous samples, and is commonly used for HPLC solvents sample preparation. The membrane is super-clean, promises low residual contamination added to the flux during the clarifying process, ensuring the analysis is not disturbed and the results are accurate.  membrane have highly excellent corrosion resistance, high flow rate and other characteristics, which can be widely used in various filtration needs, such as Industrial wastewater, laboratory drugs, semiconductor cutting fluid, aquaculture and fishery, food processing, livestock wastewater, etc.