Our research focuses on controlling materials at the 100-nanometer scale and investigating their size and shape-dependent properties. We have developed massively parallel, multi-scale nanopatterning tools to generate noble metal (plasmonic) structures that can manipulate visible light at the nanoscale. We are focusing on multi-scale, anisotropic, and 3D plasmonic materials for applications in imaging, sensing, and cancer therapeutics.
Superhydrophobic surfaces that can also withstand mechanical deformation such as bending and stretching are important for applications such as robust self-cleaning, water-resistant electronics, and flexible microfluidics. We developed monolithic, multi-scale poly(dimethylsiloxane) (PDMS) nanowrinkles that can exhibit stretchable superhydrophobicity using high fidelity pattern transfer. The droplet impact dynamics revealed that droplet rebound depended strongly on the structural hierarchy of the surface. In particular, on three-generation hierarchical wrinkles, superhydrophobic bouncing was observed with identical droplet spreading and recoiling speed before and after 100% stretching. We attribute this robust and unusual response to the substrate being able to achieve partial preservation of the 3D structural hierarchy under stretching. Moreover, the monolithic hierarchical wrinkles showed excellent mechanical durability, where no cracking or structural defects were observed even after 1000 stretch-release cycles.