Effect of calcium ions on the interactions between surfaces end-grafted with weak polyelectrolytes.

摘要: We study the interactions between two planar surfaces end-tethered with poly(acrylic acid) polymers in electrolyte solutions containing calcium ions, using a molecular theory. found that by adding divalent ions to an aqueous solution of monovalent leads dramatic reduction size and range effective polymer layers. This is caused formation favorable bridges, i.e., complexes one ion carboxylic acid monomers, reduce charge layers and, at sufficient concentrations, can cause collapse. For concentrations above approximately 1 mM, repulsions opposing end-grafted disappear attractions occur. These are correlated occurrence interlayer bridges do not occur for contact reservoir only ions. result indicates suitability control change interaction strength, which useful property desirable design stimuli-responsive nanomaterials.