Semipermeable membranes - (Mar/14/2019 )

Hello

Does anyone have knowledge/experience with semipermeable membranes? That allow specific molecules to pass through and prevent others?

What are their disadvantages? Is pressure needed to be applied? Do they decrease the diffusion rates?

Thanks

-electros-

depends on the membrane system. spin filters do not require additional pressure while filter cells do. many are excluded by molecular size. some are non-aqueous and require whetting.

molecular size exclusion membranes are sensitive to scratching. also, if you store used filters in alcohol (as recommended) do not use denatured alcohols (i made that mistake once and ruined the membrane).

-mdfenko-

Thanks but I don't understand what you mean by this 'many are excluded by molecular size'

-electros-

Also, what about diffusion rates? Are they decreased significantly?

Also, is there a company who makes and sells semipermeable membranes for life science experiments? Can't find any in the UK.

-electros-

Google the terms you are unsure of - think a little. Size exclusion - might mean what in terms of proteins?

try Millipore.com

-bob1-

bob1 on Fri Mar 15 14:37:16 2019 said:

Google the terms you are unsure of - think a little. Size exclusion - might mean what in terms of proteins?

try Millipore.com

and search "amicon" at the millipore site

-mdfenko-

mdfenko on Mon Mar 18 19:23:54 2019 said:

bob1 on Fri Mar 15 14:37:16 2019 said:

Google the terms you are unsure of - think a little. Size exclusion - might mean what in terms of proteins?

try Millipore.com

and search "amicon" at the millipore site

Thanks, but I am looking for semiperpeable membranes that do not require force, spinning, pressure etc.

I am looking for them to work in normal static solutions.

Are there any?

For example, if we have a solution with small and large molecules, can I use a membrane to isolate the small ones from one side of the solution? (I understand not all will be isolated as diffusion will occur both directions, but I expect from the membrane side, only small molecules to diffuse and not large ones, so that side, the solution will be only with small molecules)

-electros-

Dialysis membranes are what you are looking for.

-bob1-