Research during FY-86 has been centered on synthesis, characterization, and rheology of co polymers of acrylamide (AM) with analogs of 3-acrylamido-3-methylbutanoate (AMB). Emphasis during the initial phase of this work has been directed toward placement of hydrophobic substitutes along the polymer backbone which would allow intermolecular associations to occur at low polymer concentration. Comparisons of N-substituted AMB and unsubstituted co polymers prepared under a previous grant are being made. Of special interest are the viscosity behavior and the electrolyte tolerance. Rheological, potentiometry, and ion binding studies of the substituted models indicate less tolerance to calcium ions than the NaAMB/AM system and support the proposed intramolecular chelation we suggested previously (DOE/BC/1032l-20). Solution behavior has been studied as a function of micro structure and molecular weight for N-substituted AMB/AM co polymers utilizing potentiometry, turbidimetry in conjunction with C-13 NMR and low angle laser light scattering. N-propyl-substituted NaAMB/AM copolymers have shown surfactant-like characteristics including the ability to emulsify hydrocarbons and greatly enhance solution viscosity in aqueous solution. Further studies on these and other N-substituted acrylamido systems are planned for FY-87. We have continued to advance our EOR polymer characterization capability. A new variable angle laser light scattering apparatus has been designed and is presently being assembled. In the past, we were restricted to a technically obsolete low angle laser light scattering spectrophotometer. The new scattering device should provide a much higher signal to noise ratio, and thus, provide more accurate EOR polymer characterization.