This online seminar aims to provide a platform to learn about cutting-edge studies on eco-materials and exchange thoughts with peers.

It is a common conception that when a material is stretched it becomes narrower. However, when an auxetic metamaterial is stretched it has the counterintuitive property of becoming wider. This is because the properties of an auxetic material are determined by its lattice arrangement and not by the materials properties of the individual solid elements. Because the expansion of the solid surface area is due to increased space between the solid elements, this allows new types of superhydrophobic, hemi-wicking, and liquid-infused surfaces.

The seminar will describe the theory for a hydrophobic bow-tie element based auxetic lattice constructed with joints that rotate under strain to create a hexagonal lattice. This creates an auxetic superhydrophobic material with a negative Poisson’s ratio with unique properties which can be converted by strain to a conventional superhydrophobic material with a positive Poisson’s ratio. It complement these theoretical ideas with experimental results using surfaces designed with micro-scale bow-tie lattice structures implemented lithographically in SU-8 and PDMS. The event will show how the wetting gives a new type of superhydrophobicity on these surfaces for different lattice configurations and will also discuss how metastable suspended droplets on these lattices convert into penetrating droplets as their surface tension is reduced.

Speaker

• Glen McHale, The University of Edinburgh, UK

Moderator

• Bin Xu, University of Northumbria at Newcastle, UK