Engineered Quartz and Kaolinite Nanoparticles in Biomedical and Reservoir Fluids: Quantifying Aggregation Behavior in Saline Water with Surfactants.

In this study, two nanoparticles (NPs) (kaolinite NP of 9 crystal units (9-[Al2Si2O5(OH)4]) and quartz NP of 18 units (18-[Si3O6])) are engineered based on the established crystal unit cell data. The aggregation behavior of NPs in saline water with a nonionic PEG-alkane surfactant (C12E3) is simulated by molecular dynamics (MD) simulations. The simulation shows a helix aggregation of quartz NPs and layer formation (surface-to-surface, surface-to-site, surface deformation) of kaolinite NPs. The simulation also shows a relatively faster aggregation of C12E3 into a spherical micelle, whereas the anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) form more complex rod-, funnel-, and slab-like clusters. The proposed kaolinite and quartz NPs have essential colloidal and interfacial properties for simulating reservoir or biomedical fluids with drugs, surfactants, or lipids. The NP design approach in this study can be easily adopted for any desired NPs for drug encapsulation and delivery or enhanced oil recovery (EOR).