Selectively Permeable Membrane

[mfeneley]

Is it possible to create an artifical selectively permeable membrane? I need one for a science fair project idea I had.

[Andy Resnick]

Selectively permeable *for what*?

Dialysis filters are selectively permeable. Any mechanical filter is selectively permeable. Put some charge on the filter and it's also selective for charged solutes.

Can we make a filter that is permeable only to Na+, for example? I don't think so.

[mfeneley]

Selectively permeable for either positve or negative molecules. I need the membrane to cause osmosis.

[Andy Resnick]

http://en.wikipedia.org/wiki/Semi-permeable_membrane has many different material options.