Drag on a spheroidal particle at clean and surfactant-laden interfaces: effects of particle aspect ratio, contact angle and surface viscosities

Abstract

Abstract

Influence of surface viscosities on the electrodeformation of a prolate viscous drop

“…Three dimensionless parameters emerge from scaling: the electric capillary number Ca E = e 2 E 0 2 r 0 /g, and the Boussinesq numbers m d = l/m 1 r 0 and m s = n/m 1 r 0 . However, the shear and dilatational viscosities may have, in exceptional cases, the same order of magnitude, 66,67 in general m d c m s . [68][69][70][71][72] For example, surface viscosity measurements for sodium lauryl sulfate (SLS; 73 In these cases, the dilatational viscosity is about 2 (SLS) to 4 (SLS-LOH) orders of magnitude larger than the shear viscosity (m d c m s ).…”

“…Three dimensionless parameters emerge from scaling: the electric capillary number Ca E = ε 2 E 0 2 r 0 / γ , and the Boussinesq numbers μ d = λ / μ 1 r 0 and μ s = ν / μ 1 r 0 . However, the shear and dilatational viscosities may have, in exceptional cases, the same order of magnitude, 66,67 in general μ d ≫ μ s . 68–72 For example, surface viscosity measurements for sodium lauryl sulfate (SLS; μ d ≈ 2.5 × 10 −3 N s m −1 , μ s ≈ 1.7 × 10 −7 N s m −1 ) or sodium lauryl sulfate–lauryl alcohol (SLS–LOH; μ d ≈ 39.8 × 10 −3 N s m −1 , μ s ≈ 0.2 × 10 −3 N s m −1 ).…”