Recent developments of auxetic metamaterials

Auxetic metamaterials, characterized by their negative Poisson’s ratio, exhibit unconventional mechanical behaviors such as lateral expansion when stretched and lateral contraction when compressed. This unique property distinguishes them from conventional materials and makes them highly versatile for various advanced applications. This review provides a comprehensive overview of auxetic metamaterial structures, focusing on their design principles, fabrication techniques, and diverse applications. The structural configurations, including auxetic foams, lattices, origami-inspired designs, and kirigami-based geometries, are discussed in detail, highlighting their deformation mechanisms and resulting properties. Fabrication methodologies, ranging from traditional manufacturing processes to advanced techniques such as additive manufacturing and laser cutting, are explored, showcasing their role in enabling precise and scalable production of auxetic materials. Applications across healthcare, sensors, and protective gear technologies are examined, emphasizing the potential of auxetic metamaterials in impact resistance, energy absorption, biomedical devices, and flexible sensors. This review underscores the transformative potential of auxetic metamaterials and identifies future research directions to enhance their functionality and integration in emerging technologies.