Nat. Commun. 7, 13140 (2016)

Wouldn't it be nice to have an elastomer that could change into any given shape? Most definitely — if only for applications like microfluidic valves, Braille readers or artificial muscles.

Andraž Rešetič and colleagues have made an important step towards the manufacture of such functional rubbers. They took low-viscosity polydimethylsiloxane, a conventional elastomer, and added elastomeric liquid-crystal microparticles exhibiting shape memory — the ability to return from a deformed state into the undeformed state through heating. Under the application of an external magnetic field, the particles collectively align, and the shape-memory effect is carried over to the macroscopic structure. Subsequent hardening via thermal treatment results in a material that will deform when heated. The composite's shape-memory behaviour depends on the concentration and distribution of the fillers — enabling control of its thermoelastic response.

The authors further showed that macroscopic bilayers of these elastomeric composites with different deformational directions can result in any of five basic thermomechanical deformation modes. The future looks bendy.