Mesoscopic simulation study on the interaction between polymer and C12NBr or C9phNBr in aqueous solution

The interaction of partially hydrolyzed polyacrylamide (HPAM) with dodecyl-oxypropyl-β-hydroxyl trimethyl-ammonium bromide (C12NBr) and nonyl-phenyl-oxypropyl-β-hydroxyl trimethyl-ammonium bromide (C9phNBr) in the solution was investigated by the Dissipative Particle Dynamics (DPD) method. The calculated interaction parameters between HPAM and C12NBr or C9phNBr showed that C12NBr is most likely to form polymer/surfactant complex with HPAM in contrast to C9phNBr. The experiment of binding isotherm was used to validate the DPD results via surfactant-selective electrode and equilibrium dialysis method. In DPD method, the mean square end-to-end distance <r2> of polymer chain firstly increased, then reduced, and finally increased again. In addition, some polymer/surfactant complexes were also shown. One conclusion is that mesoscopic simulation can be considered as an adjunct to experiments and provide otherwise inaccessible (or not easily accessible) information in the experiment.