Characterizing the membrane properties of capsules flowing in a square-section microfluidic channel: Effects of the membrane constitutive law

摘要

Amicrofluidic method is presented tomeasure the elastic membrane properties of a population ofmicrocapsulesnwith diameter of order 60 μm. The technique consists of flowing a suspension of capsules enclosed byna polymerized ovalbumin membrane through a square-section microfluidic channel with cross dimensionncomparable with the capsule mean diameter. The deformed profile and the velocity of a given capsule arenrecorded. A full mechanical model of the motion and deformation of an initially spherical capsule flowing insidena square-section channel is designed for different flow strengths, confinement ratios, and membrane constitutivenlaws. The experimental deformed profiles are analyzed with the numerical model. This allows us to find the rationbetween the viscous and elastic forces and thus the shear elastic modulus of the membrane. We show that thenovalbumin membrane tends to have a strain-softening behavior under the conditions studied here.