Modeling the Assembly of Polymer-Grafted Nanoparticles at Oil–Water Interfaces

Abstract

Using dissipative particle dynamics (DPD), I model the interfacial adsorption and self-assembly of polymer-grafted nanoparticles at a planar oil-water interface. The amphiphilic core-shell nanoparticles irreversibly adsorb to the interface and create a monolayer covering the interface. The polymer chains of the adsorbed nanoparticles are significantly deformed by surface tension to conform to the interface. I quantitatively characterize the properties of the particle-laden interface and the structure of the monolayer in detail at different surface coverages. I observe that the monolayer of particles grafted with long polymer chains undergoes an intriguing liquid-crystalline-amorphous phase transition in which the relationship between the monolayer structure and the surface tension/pressure of the interface is elucidated. Moreover, my results indicate that the amorphous state at high surface coverage is induced by the anisotropic distribution of the randomly grafted chains on each particle core, which leads to noncircular in-plane morphology formed under excluded volume effects. These studies provide a fundamental understanding of the interfacial behavior of polymer-grafted nanoparticles for achieving complete control of the adsorption and subsequent self-assembly.

Oil Sorbents based on Methacrylic Acid - Grafted Polypropylene Fibers: Synthesis and Characterization

“…This can be demonstrated by a high linear correlation coefficient R 2 =0.9908. This also proved that the sorption of oil on the grafted fibers was monolayer sorption [53,54]. From the obtained equation (Figure 10), we can identify the maximum oil sorption capacity is Q max =1/0.048=20.833 (g/g).…”

Building Reconfigurable Devices Using Complex Liquid–Fluid Interfaces

“…Molecular simulations predict that the conformation of ligands grafted onto the NP surface can change upon adsorption to the interface due to the asymmetric environment surrounding the particles . Yong characterized the adsorption process, i.e., approaching and breaching of the interface, and subsequent change in conformation, of polymer‐grafted NPs via molecular simulation . They observed that grafted chains can undergo significant reconfiguration during adsorption by spreading onto the interface to maximize the reduction in surface tension (Figure a–f), indirect evidence for which has also been seen experimentally .…”

“…a–f) Snapshots of adsorption simulation of a single NP grafted with hydrophilic polymer chains. Reproduced with permission . Copyright 2015, American Chemical Society.…”

Effect of Nanoparticles on Spontaneous Imbibition of Water into Ultraconfined Reservoir Capillary by Molecular Dynamics Simulation

“…Meanwhile, experimental results by Wasan and Nikolov [26] showed that the nanoparticles could form two-dimensional (2-D) layered structures in the confines of the three-phase (solid-oil-aqueous phase) contact region and produce disjoining pressure that leads to the wettability alteration of the solid phase. Therefore, it has been believed that nanoparticles can change the interfacial tension, viscosity and wettability of fluids, which are important to many applications ranging from electronics cooling to oil recovery [30][31][32][33][34]. However, due to the additional particle-particle, particle-capillary and particle-fluid interactions [32,35], the presence of nanoparticles leads to a much more complicated imbibition process compared with pure fluids.…”