A method of manufacturing a foam having a Poisson's ratio which varies across at least a region of the foam in a gradient distribution involves the steps of: a) providing a housing defining an internal space having an inlet aperture and an outlet aperture; b) providing an open-cell foam of a size and shape configured to fit inside the internal space of the housing; c) positioning the foam inside the internal space of the housing; d) establishing a flow of air through the foam via the inlet and outlet apertures; e) heating the foam to a predetermined temperature while maintaining the flow of air through the foam; and f) subsequently cooling the foam while continuing to maintain the flow of air through the foam. A foam of such a type is also presented.