What is the difference between PVDF microporous membrane and NC filter membrane?

PVDF (polyvinylidene fluoride) and NC (nitrocellulose) are two different types of filter membrane materials used in a variety of applications. Here are the detailed differences between them:

Material:

PVDF: PVDF is a thermoplastic fluoropolymer with excellent chemical resistance, mechanical strength and thermal stability. It is known for its high purity and low protein binding properties, making it suitable for applications requiring minimal interaction with filter substances.

NC: Nitrocellulose is a highly flammable compound derived from cellulose through nitration. It is commonly used as a filtration membrane material due to its hydrophilicity and ability to immobilize biomolecules through adsorption.

Molecular Structure:

PVDF: PVDF has a linear polymer chain structure composed of repeating units of vinylidene fluoride monomer (CH2CF2). The strong carbon-fluorine bonds in this type of polymer chain make it difficult for most molecules to invade, even in harsh environments. PVDF membrane can also show excellent chemical resistance under environmental conditions, such as resistance to acids, alkalis, solvents and oxidants.

NC: Nitrocellulose has a complex structure resulting from the nitration of cellulose. Nitrocellulose molecules contain nitrate groups (-NO2) attached to the cellulose backbone. Due to the presence of nitrate groups, nitrocellulose is highly reactive. NC membrane has high protein binding capacity and is suitable for protein analysis and immunoassay. Compared with PVDF membrane, NC membrane is relatively more fragile and more susceptible to mechanical damage.

Production Process:

PVDF: PVDF membranes are typically produced through processes such as phase inversion or melt extrusion, followed by stretching or casting techniques. For example, PVDF can be dissolved in a solvent to form a film and then solidified by precipitation or cooling to form a film.

NC: Nitrocellulose membranes are made by dissolving nitrocellulose flakes in a mixture of organic solvents, then casting or spraying the solution onto the surface of the substrate, where the solvent evaporates, leaving a thin film of nitrocellulose.

application:

PVDF: PVDF membranes are widely used in various filtration applications due to their excellent chemical compatibility and low protein binding properties in industries such as pharmaceuticals, biotechnology, food and beverage processing, electronics manufacturing, and water treatment.

NC: Nitrocellulose membranes are widely used in biological research and diagnosis due to their ability to immobilize biomolecules such as proteins or nucleic acids for detection, such as Western blotting, dot blot assays, enzyme-linked immunosorbent assays (ELISA), and lateral flow assays. (such as pregnancy tests) and nucleic acid hybridization experiments.

To sum up, PVDF filter membrane is superior to NC membrane in terms of chemical resistance, thermal stability and mechanical strength. Similarly, NC filter membrane has higher protein binding capacity and hydrophilic properties, which PVDF membrane does not have. Yes, they each have their own advantages. In practical applications, you can choose according to the industry and your own needs.