Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Focus: Droplets (joint session DY/CPP)

CPP 18.6: Talk

Monday, March 12, 2018, 16:45–17:00, BH-N 334

Spontaneous jumping, bouncing and trampolining of hydrogel drops on a heated plate — •Doris Vollmer¹, Jonathan Pham¹, Sanghyuk Wooh¹, Tadashi Kajiya^1,2, and Hans-Jürgen Butt¹ — ¹Max Planck Institute for Polymer Research, Mainz, Germany — ²Analysis Technology Center, Fujifilm, Nakanuma, Japan

We study the dynamics of hydrogel drops, i.e. sold drops containing up to 97% of water. Using high speed video microscopy, we demonstrate that hydrogel drops, initially at rest on a surface, spontaneously jump upon rapid heating and continue to bounce with increasing amplitudes. Jumping is governed by the surface wettability, surface temperature, hydrogel elasticity, and adhesion. A combination of low adhesion impact behavior and fast water vapor formation supports continuous bouncing and trampolining. Our results illustrate how the interplay between solid and liquid characteristics of hydrogels results in intriguing dynamics, as reflected by spontaneous jumping, bouncing, trampolining, and extremely short contact times.

J.T. Pham, M. Paven, S. Wooh, T. Kajiya, H.-J. Butt, D. Vollmer, Nat. Comm., 2017, 8, 905