Kosmotropes and chaotropes: Specific ion effects to tailor layer-by-layer membrane characteristics and performances

So-called specific ion effects strongly impact physicochemical phenomena in among others, morphologies of polymeric membranes. This can be correlated to the identity ions, rather than just their charge or concentration. We use this effect tune properties layer-by-layer membranes prepared with polyelectrolytes polydiallyldimethylammonium chloride and polystyrene sodium sulfonate. To systematically study this, were using different salts (NaBr, NH4Cl, MgCl2, NaCl, LiCl, MgSO4, NaH2PO4, (NH4)2SO4, Na2SO4). The evaluated thanks classification PEs into kosmotropes (well hydrated) chaotropes (poorly following law matching water affinities (LMWA). type anions cations on multilayer formation membrane performances was evaluated. Membranes kosmotropic achieved stable after only 4 bilayers, almost 6 times higher permeabilities chaotropic without compromising often even improving membrane's size exclusion behaviour. used tuned charge: Kosmotropic delivered negatively charged Na2SO4 MgCl2 retentions till 97% 10% respectively, while formed more positively reversed behaviour rejection 20 89%.