(580j) Interfacial Rheological Behavior of Janus Particles at the Air-Water Interface

Janus particles, named after the two-faced Roman god, derive their name by possessing two distinctly different surface properties. In comparison to their homogeneous analogs, Janus particles offer a unique potential in a range of applications involving interfacial systems owing to their tunable surface properties and enhanced binding energies to fluid interfaces. In a variety of these applications, the interfacial system will be subjected to deformations; therefore, the response of particle-laden interfaces to the applied deformation can impact the performance and stability. Understanding the flow behavior of colloidal monolayers and the role particle amphiphilicity plays in the resulting interfacial rheology can help with an effective engineering of fluid interfaces. Despite the large body of work on the rheology of systems composed of homogeneous particles with uniform surface wettability, tuning the interfacial rheology in a Janus system is relatively unexplored. In this work, we have examined the rheology of particle-laden interfaces as a function of particle amphiphilicity to investigate the relationship between the interparticle interactions, interfacial microstructure, and the resulting response of the interfacial layer. Our findings illustrate the influence of particle surface properties on the flow behavior of interfaces decorated with colloidal particles.