Effect of Self-Aggregation Behavior of Geminized Cationic Amphiphilic Macromolecules on the Removal Mechanism of Asphaltenes

A novel kind of geminized cationic amphiphilic polymer, PAGBn, was synthesized and used for an asphaltenes desorption study by exposing preadsorbed asphaltene layers to PAGBn aqueous solution with different concentrations. The asphaltenes adsorption/desorption process was characterized by quartz crystal microbalance with dissipation (QCM-D), atomic force microcopy (AFM) and contact angle (CA) measurements. The desorbed mass of asphaltenes from QCM-D is increased from ∼31.6 to ∼799.5 ng/cm2 with increasing PAGBn concentrations from 0.5 × CAC to 10.0 × CAC and an obvious improvement occurs at 5.0 × CAC. Combined with the results of desorbed mass, AFM images, and surface wettability, a gradual “peeling off” process of asphaltenes displaced by PAGBn aggregates from the solid/liquid interface can be speculated, in which these asphaltenes were pushed into sporadic larger blocks and detached away from the silica surfaces. The self-aggregation behavior of PAGBn on the solid–liquid interface was further investigated through dynamic light scattering (DLS) and transmission electron microscopy (TEM). A network aggregates consisting of many spherical multisize micelles was formed by amphiphilic polymers, and a deep removal mechanism of asphaltenes from solid surface was reasonably proposed, shedding light on the improvement of heavy oil recovery.