Classification of Auxetic Materials: A Focus on Natural and Synthetic Types

Auxetic materials, which feature a negative Poisson’s ratio, demonstrate the unusual behavior of expanding laterally when pulled and contracting when compressed. These materials possess a range of applications thanks to their enhanced characteristics, including better energy absorption, resistance to indentation, and flexibility. Auxetic materials can be generally divided into two types: natural and synthetic. Natural auxetic materials are found in nature and include biological tissues, plant structures, and specific natural crystals that show a negative Poisson’s ratio due to their structural configurations. In contrast, synthetic auxetic materials are artificially created to display auxetic properties, typically achieved through engineered designs, polymer frameworks, and cutting-edge manufacturing methods like 3D printing.