What Are PVDF and the PVDF Filter Membrane?

What is PVDF?

PVDF, the abbreviation of polyvinylidene fluoride, mainly refers to the homopolymer of vinylidene fluoride or the copolymer of vinylidene fluoride and a small amount of other fluorine-containing vinyl monomers. The membrane manufacturer provided us with PVDF, which has the characteristics of both fluorine resin and general resin. In addition to good chemical resistance, high-temperature resistance, oxidation resistance, weather resistance, and radiation resistance, it also has special properties such as piezoelectricity, dielectric properties, and pyroelectric properties. It ranks second in the production of fluorine-containing plastics. The annual production capacity is more than 43,000 tons.

The chemical structure is combined with a fluorine-carbon bond. This structure with short bond properties forms a stable and firm bond with hydrogen ions. Therefore, fluorocarbon coatings have specific physical and chemical properties, not only having strong wear resistance and impact resistance but also having high fading resistance and UV resistance in harsh and harsh environments.

Polyvinylidene fluoride (PVDF)’s appearance is a translucent or white powder or particles, with molecular chains closely arranged, and there are strong hydrogen bonds. Its oxygen index is 46%, non-combustible, crystallinity is 65%~78%, density is 1.17~1.79g/cm3, melting point is 172℃, heat distortion temperature is 112~145℃, long-term use temperature is -40~150℃. PVDF is a PVDF fusible fluorocarbon resin for coatings made by the homopolymerization of vinylidene fluoride (VDF) with a purity of ≥99.99%. The fluorocarbon coating made of 70% PVDF resin is sprayed or rolled and baked into the paint film, which has superior weather resistance and processing performance.

What is a PVDF membrane filter?

PVDF filter is a solid support commonly used in Western blotting. Use a 0.45 μm membrane for proteins larger than 20000, and a 0.2 μm membrane for proteins smaller than 20000. PVDF membranes need to be pre-treated for use. To activate the positively charged groups on the membrane, making it easier to bind negatively charged proteins, is the methanol treatment.

PVDF filter membrane has high mechanical strength and is an ideal solid support material in the imprinting method. Its performance is better than pure PVC membrane material, and the price is correspondingly slightly higher than that of pure PVC membrane material. Compared with ordinary PVC membranes, PVDF membranes have improved durability of about 7~10 years.

As a kind of hydrophobic membrane and solid support commonly used in Western blotting with high mechanical strength, the PVDF membrane filter’s pore size can be small or large. The membrane’s binding ability to low-molecular-weight proteins will become firmer, with the membrane continuing to decrease. The use of PVDF membrane requires pretreatment with methanol, which aims to activate the positively charged groups, making it easier to bind to negatively charged proteins. PVDF filters are an ideal choice for various staining applications and multiple immunoassays, and the lane copy of a single gel can be used for multiple purposes, especially when N-terminal protein sequencing is required.

Hydrophilic VS. Hydrophobic PVDF Membranes：

Hydrophilic PVDF: Suitable for aqueous solution filtration without pre-wetting. Ideal for protein-containing samples or cell culture media.
Hydrophobic PVDF: Best for filtering non-polar solvents and gases. Requires pre-wetting with alcohol if used for aqueous solutions.

Classification of PVDF filter membrane

1. PVDF membranes for water treatment: There are two types of ultrafiltration membranes and microfiltration membranes. They are mainly used for pre-treatment of sewage, seawater desalination, etc., to remove macromolecules, bacteria, silt, etc.
2. PVDF membranes for different batteries, such as the lithium-ion polymer battery and fuel cells, and so on.
3. PVDF membranes for outdoor construction, the main use is the protection of outdoor construction glass, exterior walls, outdoor billboards, etc., mainly for aging resistance and wear resistance.

Key Features of PVDF Filter Membranes

• Low protein binding – excellent for biological and pharmaceutical samples
• High flow rate – faster filtration with minimal pressure drop
• Broad chemical compatibility – suitable for aggressive solvents and buffers
• Autoclavable – compatible with steam sterilization
• High purity – minimal interference with analytical results

Compared with materials like nylon or PES, PVDF stands out in applications where protein recovery, chemical resistance, and membrane cleanliness are critical.

Common Applications of PVDF Filter Membranes

PVDF membranes are widely used across multiple industries, including:

• Life sciences: protein filtration, cell culture media filtration, vaccine preparation
• Pharmaceuticals: sterile filtration, drug formulation clarification
• Analytical laboratories: HPLC sample preparation, solvent filtration
• Environmental testing: water and wastewater analysis
• Gas filtration: air vents and sterile gas transfer

Their versatility makes PVDF a preferred choice in both research laboratories and industrial production environments.

The main performance of the PVDF filter membrane

· High purity
· Anti-fungal
· Easy to melt processing
· Flame retardant, low smoke
· High abrasion resistance
· Both rigid and flexible forms
· Impact resistance
· Weather resistance
· Good heat stability
· UV and nuclear radiation resistance
· Low-temperature resistance up to -40℃
· Resistant to most chemicals and solvents
· High mechanical strength and toughness
· High resistance to gas and liquid permeability
· Good creep resistance during the temperature increase

PVDF membrane soaking steps

PVDF is essentially a hydrophobic polymer and will not wet out in an aqueous solution. In order to use PVDF membranes in aqueous buffers and systems, they must first be immersed in a 50% (v/v) or higher concentration alcohol solution. Other suitable solutions for soaking this membrane are methanol, ethanol, and isopropanol. As the appearance of the membrane changes from opaque to translucent, complete wetting is evident. After that, it must be rinsed repeatedly with water to remove the alcohol, and the pre-treated membrane can now be directly placed in the transfer buffer to equilibrate.

Wet transfer:
(1) Soak the membrane in methanol for 30 seconds. The membrane should change uniformly from opaque to translucent.
(2) Carefully put the membrane into double-distilled water and soak for 2 minutes.
(3) Carefully put the membrane in the transfer buffer and equilibrate for at least 5 minutes.

Semi-dry transfer:
The first methanol soaking takes only 15 seconds, and the other steps are the same as above.

Click here to know The Differences Between PVDF and PTFE Membrane.