Reticulated foam

Reticulated foam is a very porous, low density solid foam. 'Reticulated' means like a net. Reticulated foams are extremely open foams i.e. there are few, if any, intact bubbles or cell windows. In contrast, the foam formed by soap bubbles is composed solely of intact (fully enclosed) bubbles. In a reticulated foam only the lineal boundaries where the bubbles meet ( Plateau borders ) remain.

The solid component of a reticulated foam may be an organic polymer like polyurethane, a ceramic or a metal. These materials are used in a wide range of applications where the high porosity and large surface area are needed, including filters, catalyst supports, fuel tank inserts, and loudspeaker covers.

A description of the structure of reticulated foams is still being developed. While Plateau's laws, the rules governing the shape of soap films in foams were developed in the 19th century, a mathematical description of the structure is still debated. The computer-generated Weaire–Phelan structure is the most recent. In a reticulated foam only the edges of the polyhedra remain; the faces are missing. In commercial reticulated foam, up to 98% of the faces are removed. The dodecahedron is sometimes given as the basic unit for these foams, but the most representative shape is a polyhedron with 13 faces. Cell size and cell size distribution are critical parameters for most applications. Porosity is typically 95%, but can be as high as 98%. Reticulation affects many of the physical properties of a foam. Typically resistance to compression is decreased while tensile properties like elongation and resistance to tearing are increased.

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