INTRODUCTION:
PVDF and nitrocellulose membranes are both used in Western blotting and have various different characteristics, however a common question asked is "Why do PVDF membranes require a methanol soak?".
Check out this blog for more on the differences of the membranes:
PVDF membrane is very hydrophobic, meaning that aqueous buffers, such as the Western transfer buffers or deionized water, will not penetrate the membrane. This results in poor transfer and significantly reduced binding of proteins.
A short rinse (15-30 seconds) in methanol (or other 100% alcohol (ethanol or isopropanol)) prior to Western transfer will "hydrate" the membrane and allow improved transfer and protein binding.
Nitrocellulose membranes are hydrophilic so can be fully hydrated by aqueous buffers.
CONCLUSION:
Soak PVDF membranes in 100% alcohol prior to assembling the Western transfer sandwich for optimal transfer and protein binding.