Ionomers are a class of polymer chains with a few, 2-10 %, ion groups substitutes onlong the chain. In order to reduce the negative interaction of the ionic group with the rest of the hydrophobic polymer matirx, the ionic groups aggregate to form 'cross links'. These aggregates dramatically effect the properties of the polymer. We are studying the tracer diffusion of a deuterated homopolymer of polystyrene, dPS, though a matix of the ionomer polystyrene-co-poly styrene sulfonate, pictured below:

Forward Angle Recoil Spectrometry, Fres, is employed to elicite the depth concentration profile of the diffusing species, dPS. A typical Fres spectum is shown below. Here a 200 A layer of 27k dPS diffuses into a 5000 A layer of the ionomer polystyrene sulfinate, 5.3% sulfonate and 0% neutralized. Preliminary results have shown that indead the diffusion is dramatically reduced by the addition of the ionic species compared to a matrix of polystyrene at a simimar molecular weight.