A letter by Liming Wang and Thomas J McCarthy* published in the current issue of PNAS.
The McCarthy group reported the preparation of particles by polymerization of liquid monomer capillary bridges to form catenoid-shaped particles that exhibit negative Gaussian curvature. The shape of the capillary bridges and resulting particles can be finely tuned using multiple addressable parameters. The catenoid-shaped particles exhibit controllable optical properties as a result of their concave menisci. The approach was scaled down to micron dimensions and arrays of millions of micron-scale particles were prepared. With special dynamic wetting behaviors, catenoid-shaped particles also exhibit interesting anisotropic adhesive properties.