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. Membrane manufacturer provide to us, PVDF 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 have strong wear resistance and impact resistance but also have high fading resistance and UV resistance in harsh and harsh environments.

Polyvinylidene fluoride (PVDF)’s appearance is a translucent or white powder or particles, molecular chains are 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 super weather resistance and processing performance.

hydrophobic ptfe membrane filter

What is a PVDF filter membrane?

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

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 pure PVC membrane material. Compared with ordinary PVC membranes, PVDF membrane has improved durability to 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 filters’ pore size can be small and large. The membrane’s binding ability to low-molecular-weight proteins will become more firmly, 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 filter 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.

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;

The main performance of the PVDF filter membrane

· High purityhydrophilic ptfe membrane filter
· Anti-fungal
· Easy to melt processing
· Flame retardant, low smoke
· High abrasion resistance
· Both rigid and flexible form
· 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.