CHAKRABARTI, Aditi; PORAT, Amir; RAPHAËL, Elie; SALEZ, Thomas; CHAUDHURY, Manoj

doi:10.1021/acs.langmuir.8b00368

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CHAKRABARTI, Aditi
Lehigh University

PORAT, Amir
Gulliver (UMR 7083)

RAPHAËL, Elie
Gulliver (UMR 7083)

Langue

Article de revue

Ce document a été publié dans

Langmuir. 2018, vol. 34, n° 13, p. 3894-3900

American Chemical Society

Résumé en anglais

When a soft hydrogel sphere is placed on a rigid hydrophilic substrate, it undergoes arrested spreading by forming an axisymmetric foot near the contact line, while conserving its global spherical shape. In contrast, liquid water (that constitutes greater than 90% of the hydrogel's volume) spreads into a thin film on the same surface. We study systematically this elastowetting of gel spheres on substrates of different surface energies and find that their contact angle increases as the work of adhesion between the gel and the substrate decreases, as one would observe for drops of pure water--albeit being larger than in the latter case. This difference in the contact angles of gel and water appears to be due to the elastic shear stresses that develop in the gel and oppose its spreading. Indeed, by increasing the elastic modulus of the gel spheres, we find that their contact angle also increases. In addition, the length of the contact foot increases with the work of adhesion and sphere size, while it decreases when the elastic modulus of the gel is increased. We discuss those experimental results in light of a minimal analysis based on energy minimization, volume conservation, and scaling arguments.< Réduire

DOI

http://dx.doi.org/10.1021/acs.langmuir.8b00368

Project ANR

Paris Sciences et Lettres - ANR-10-IDEX-0001

Origine

Importé de hal

Unités de recherche

Laboratoire Ondes et Matière d'Aquitaine (LOMA) - UMR 5798