Effect of poly(methyl methacrylate) particles on the initiation of instability in the capillary thinning of poly(ethylene oxide) solution

Abstract

The effect of particles on the instability in the capillary thinning process of poly(ethylene oxide) solution has been experimentally studied to further understand the filament breakup behavior of the particulate systems. We focus on breathing and the formation of the 1st bead, in particular, which initiates blistering. The change in instability pattern by the added PMMA particles is investigated by observing the evolution of the filament undergoing capillary thinning. Addition of particles accelerates breathing and the formation of the 1st bead. By comparing the extensional properties of PMMA/PEO suspension with that of Glycerin/PEO solutions which has the same viscosity, surface tension and polymer concentration, we confirm that the early occurrence of the instability is ascribed to the inhibition on chain extension due to the presence of particles. The addition of particles has an influence on the position of the 1st bead. For a pure polymer solution and polymer solution with a small amount of particles (~2 wt%), the 1st bead mostly appears near the upper neck. However, as the particle concentration increases up to 10 wt%, the 1st bead is formed anywhere along the filament with similar probability. The randomization of the position of the 1st bead is attributed to the non-uniform distribution of particles inside a filament by the fluctuation of the local particle concentration.