Controlling interface topography via degradation of soft nanogel particles adsorbed at a liquid-liquid interface

Adsorption of nanogel and microgel particles onto liquid-liquid interfaces finds several potential applications. In this work, we study controlled degradation of nanogels as a means to dynamically control the topography of soft nanostructured interfaces. We use the Dissipative Particle Dynamics (DPD) simulation approach, along with an adapted form of the modified Segmental Repulsive Potential (mSRP) to characterize degradation of nanogels at the interface. We first simulate degradation of single nanogel particles suspended in a solvent and track the evolution of particle size, and shape via the gyration tensor up to the reverse gel point, where nanogel particles completely dissolve in the solvent. We show that the nature of the polymer-solvent interaction significantly affects the evolution of shape during degradation. Further, we simulate the adsorption and spreading of these nanogels onto the interface between two liquids and observe that this process is affected significantly by the strength of the repulsion between the two liquids. We compare the size and shape evolution of nanogels degrading at the interface with those degrading in the bulk and measure an extent of spreading during degradation. Our results indicate that controlled degradation of the nanogels results in an enhanced extent of interfacial spreading and provides a way to control interface topography at the nanoscale.