(438g) Topological Interactions of Spiky Particles with a Planar Wall

The study of the interactions of spiky colloids with substrates is of interest for different applications, such as drug delivery, energy, filtration, etc. Spiky colloidal particles are commonly seen in nature; however, considerable experimental and theoretical evidence diminishes the effectiveness of their adhesion. In this study, we model the DLVO interactions of a spiky particle with a planar wall using the extended Surface Element Integration approach, including the effects of particle position and orientation. The spiky particle’s topography is modeled using a spherical core with uniform and normally distributed ellipsoidal spikes over its surface. The effect of spike aspect ratio, particle-wall separation distance, and particle orientation on interaction energy and adhesion were studied and compared with a smooth sphere-wall interaction.

Results show that the DLVO interaction energy is highly dependent on the relative particle orientation with respect to the wall. The spiked configurations showed a dual effect in adhesion energy and force, with larger spikes yielding higher adhesion while shorter spikes yielded lower adhesion than the smooth sphere. Furthermore, results indicate that the spikes promote resistive torques, showing how the spiky particles enhance the particle interaction with planar substrates. Additionally, we developed a simplified model to describe the DLVO interactions based on the topological features of the distribution of the spikes in the orientational space and independent of the spike aspect ratio.