To Construct 'Ion Traps' for Enhancing the Permselectivity and Permeability of Polyelectrolyte Multilayer Films

摘要

We introduced single-charged molecules into layer-by-layer film of polymers by mixing polyelectrolyte and single-charged molecules with an appropriate ratio to form polymer complex and then deposition in alternation with counter-polyelectrolyte.By immersing the layer-by-layer film into aqueous solution of electrolytes,the single-charged molecules could be released from the layer-by-layer film.An interesting finding is the releasing of the single-charged molecules gave the multilayer film the permselectivity.For example,cations would be trapped and anions be repelled if positive-charged molecules were used.Multilayer films able to trap either cations or anions could be fabricated,depending on the nature of single-charged template molecules used.Thus,the ion permselectivity of multilayer film was enhanced.Moreover,the permeability of the film was also dramatically increased,suggesting the potential application of layer-by-layer films as highly efficient ion-permselective membranes.