What does MMB stand for?

Membrane

A flexible or semi-flexible roof covering or waterproofing layer, whose primary function is the exclusion of water. A continuous layer covering a structure or separating two electrolytic solutions. The membrane of an ISE is responsible for the potential response and the selectivity of the electrode. A sheet-like composite of protein and lipid that is the boundary of cells and organelles. A barrier, usually thin, that permits the passage only of particles up to a certain size or of special nature. A thin sheet or layer.