Mechanical metamaterial with improved compressive responses

A mechanical metamaterial with high compressibility comprising a first unit layer and a second unit layer that are repeatedly and alternately stacked or layered in a height direction into a three-dimensional structure, wherein:

• the first unit layer comprises multiple first structure units which are repeatedly and regularly composed in a horizontal direction along a plane surface of the first unit layer, and the first structure units include six-bonded chiral structures;
• the six-bonded chiral structure is a structure having six-bonds extending outwardly and radiating from a center circle at equal angles in the plane surface of the first unit layer;
• the second unit layer comprises multiple second structure units which are repeatedly and regularly composed in a horizontal direction along a plane surface of the second unit layer, and the second structure units includes four annular reentrant structures;
• the four annular reentrant structure is a structure having a three-dimensional square structure formed by connecting four circles or rings;
• a width of each bond of the six-bonded chiral structure and a line diameter of the four annular reentrant structure are between 0.10 mm and 0.50 mm;
• the mechanical metamaterial comprises an elastic photocurable resin impregnated with carbon nanotubes modified with surface functional groups;
• the functional groups include hydroxyl (—OH), aldehyde (—CO—), or carboxyl (—COOH) groups, or a combination thereof;
• and
• the elastic photocurable resin includes polyurethane (PU), thermoplastic polyurethane (TPU), rubber, silicone resin or a combination thereof.