Controllable thermal expansion of large magnitude in chiral negative Poisson's ratio lattices

Lattices of controlled thermal expansion are presented based on planar chiral lattice structure with Poisson's ratio approaching − 1 . Thermal expansion values can be arbitrarily large positive or negative. A lattice was fabricated from bimetallic strips and the properties analyzed and studied experimentally. The effective thermal expansion coefficient of the lattice is about α = − 3.5 × 10 − 4 K− 1 . This is much larger in magnitude than that of constituent metals. Nodes were observed to rotate as temperature was changed corresponding to a Cosserat thermoelastic solid.