Adsorbed monomer analog of a common polyelectrolyte

The monomer analog of a common water-soluble charged macromolecule shows surface tilt and cooperative adsorption that would be expected for larger surfactant molecules-the small organic ion behaves as an embryonic surfactant. Yet the organic ion competes with inorganic ions (Na+, Mg++, etc.) for access to the surface, and therefore its tilt increases with the size of the competing co-ion. Similar ordering of charged units along a polyelectrolyte chain would be sterically frustrated. This suggests a new contribution to surface energetics when a charged macromolecule adsorbs.