Soft Matter and Complex Systems Seminar

Formation of droplets is a fundamental process used in many industrial applications, such as inkjet printing and drug manufacturing. These droplets are often formed from the break-up of a liquid thread driven by a surface tension dependent instability, namely the Rayleigh-Plateau instability. We can reduce the surface tension by adding surfactants, which are molecules that adsorb on the interface of liquids, and thus, change the break-up dynamics. At certain systems with ultra-low surface tension or very small length scales, thermal fluctuations on the interface are capable of creating the instability that leads to the formation of droplets and satellite droplets. In our study, we employ simulations of a coarse-grained model known as many-body dissipative particle dynamics (MDPD) to determine the characteristic wavelength of such instabilities on liquid nanothreads with various surfactant concentrations, above and below its critical aggregation concentration. Also, we have identified the different break-up regimes, their time-scales and local concentration distributions that develop due to surfactant advection . We anticipate that our study contributes to the understanding of a fundamental process in nature and paves the way for further developments in this area for relevant applications.