Principal Investigator Evelyn Wang
We developed omniphobic, doubly reentrant surfaces shows the fabrication process, in which esfabricatedwithasimplemethodsuitableforuse standard photolithography and etches used to with traditional microfabrication processes. Intrinsic stresses in deposited layers of silicon nitride induced bending of a singly reentrant microstructure, creating the doubly reentrant geometry. Due to the use of standard microfabrication processes, this approach may be extended to a variety of materials and feature sizes, increasing the viability of applying omniphobic doubly reentrant structures for use in areas such as superomniphobicity, anti-corrosion, heat transfer en- hancement, and drag reduction.
We show the fabriation process, in which standard photolithography and etches used to create singly reentrant microstructures are adopted. However, due to the stresses in deposited layers of silicon nitride, the singly reentrant structure is bent into a doubly reentrant geometry that renders the surface omniphobic. We also show the contact angle of water and FC 40 on the surface. FC 40 has a much lower surface tension than water, which typically makes it difficult to repel. However, due to the double reentrant geometry of this surface, it is repelled.