Ultralight, Soft Polymer Sponges by Self‐Assembly of Short Electrospun Fibers in Colloidal Dispersions

Ultralight polymer sponges are prepared by freeze‐drying of dispersions of short electrospun fibers. In contrast to many other highly porous materials, these sponges show extremely low densities (<3 mg cm −3 ) in combination with low specific surface areas. The resulting hierarchical pore structure of the sponges gives basis for soft and reversibly compressible materials and to hydrophobic behavior in combination with excellent uptake for hydrophobic liquids. Owing to their large porosity, cell culturing is successful after hydrophilic modification of the sponges.