Spongy Gels by a Top‐Down Approach from Polymer Fibrous Sponges

Ultralight cellular sponges offer a unique set of properties. We show here that solvent uptake by these sponges results in new gel‐like materials, which we term spongy gels. The appearance of the spongy gels is very similar to classic organogels. Usually, organogels are formed by a bottom‐up process. In contrast, the spongy gels are formed by a top‐down approach that offers numerous advantages for the design of their properties, reproducibility, and stability. The sponges themselves represent the scaffold of a gel that could be filled with a solvent, and thereby form a mechanically stable gel‐like material. The spongy gels are independent of a time‐consuming or otherwise demanding in situ scaffold formation. As solvent evaporation from gels is a concern for various applications, we also studied solvent evaporation of wetting and non‐wetting liquids dispersed in the sponge.