title: Transient behavior and relaxation of microcapsules with a cross-linked human serum albumin membrane.
abstract: Capsules consist of droplets enclosed by a membrane with shear resistant properties especially when fabricated by interfacial cross-linking. In many applications, the protection and release of the internal medium need to be strictly controlled. It is possible to tune the membrane mechanical properties by changing the physico-chemical conditions of the fabrication process, but a good control of the production requires their characterization, which is a scientific challenge, since the objects are a few tens of microns in size at most. One advantageous approach is to resort to microfluidic techniques. We study the transient response of capsules having a cross-linked human serum albumin (HSA) membrane, as they flow through a sudden expansion. We determine the characteristic time scales of the capsule relaxation and compare them to the ones predicted by a full numerical model of the relaxation of a capsule flowing in a rectangular channel, for which the membrane is assumed to be purely elastic. We show that the membrane is viscoelastic and that the relaxation is solely a function of the ratio of the relaxation time to the convective time.
authors.affiliation: Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de technologie de Compiègne - CNRS, Sorbonne université, CS 60319, 60203 Compiègne, France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Gires
authors.affiliation: Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de technologie de Compiègne - CNRS, Sorbonne université, CS 60319, 60203 Compiègne, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Barthès-Biesel
authors.affiliation: Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de technologie de Compiègne - CNRS, Sorbonne université, CS 60319, 60203 Compiègne, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Leclerc
authors.affiliation: Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de technologie de Compiègne - CNRS, Sorbonne université, CS 60319, 60203 Compiègne, France. Electronic address: a.salsac@utc.fr.
authors.forename: Anne-Virginie
authors.initials: AV
authors.lastname: Salsac
mesh_terms: D002214:Capsules / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D006801:Humans; D008567:Membranes, Artificial; D046210:Microfluidic Analytical Techniques; D012709:Serum Albumin / Q000737:chemistry*
chemical_list: D002214:Capsules; D003432:Cross-Linking Reagents; D008567:Membranes, Artificial; D012709:Serum Albumin
keywords: Fluid structure interactions; Mechanical characterization; Microcapsules; Microfluidic experiment; Relaxation