Investigation into micro-physicochemical interaction between sodium dodecylbenzene sulfonate (SDBS) and partially hydrolyzed polyacrylamide (HPAM) utilizing electron probe microanalysis method

Abstract After adding a surfactant to the polymer solution, the interaction between them has a significant influence on the oil recovery of polymer/surfactant (SP) flooding. The study of the micro-physicochemical interaction between sodium dodecylbenzene sulfonate (SDBS) and partially hydrolyzed polyacrylamide (HPAM) can contribute toward an understanding of the action of SP flood. In this paper, the characteristic interaction parameter (CAC and PSP) was determined by tensiometry, the microstructure of HPAM and SP solution was observed with electron probe microscope, then the distribution of SDBS in the mixtures of HPAM and SDBS was determined based on the characteristic of Sulfur. Results show HPAM and SDBS begin to aggregate after the CAC and HPAM is saturated by SDBS above the PSP. HPAM molecules in aqueous solution have a multilayer three-dimensional network structure in the form of aggregates. Most structures are hexahedral, in which there are solid backbones attached with thin branches, the mesh is from 10 μm to 100 μm. Compared with HPAM, the size of the mesh in the sample of SP solution has no noticeable change, but the network layer is reduced, the density of mesh is decreased, the rough skeleton becomes more substantial, and the branch is less. The thin films occasionally scattered in the mixtures of HPAM and SDBS. Approximate 50% of the SDBS in the solution formed aggregates with HPAM molecules by hydrophobic interaction.