Void-based metamaterials

A metamaterial unit comprising:

• a matrix comprising a plurality of unit-cells;
• at least one void within at least one unit-cell of the plurality of unit-cells;
• and
• a content of interest trapped within the at least one void, wherein the content of interest is freely movable within the at least one void, thereby providing a respective unit-cell with an intended predetermined property associated with the presence of the content of interest within the at least one void, wherein the matrix comprises an embedded metallic wire coiled surrounding at least a portion of the at least one void.

A metamaterial unit comprising:

• a matrix comprising a plurality of unit-cells;
• at least one void within at least one unit-cell of the plurality of unit-cells;
• and
• a content of interest trapped within the at least one void, wherein the content of interest is freely movable within the at least one void, thereby providing a respective unit-cell with an intended predetermined property associated with the presence of the content of interest within the at least one void, wherein a connective element differing in its structure from that of the matrix, extends between a pair of neighboring voids and is connected at either of its remote ends to a non-fluidic rigid content of interest trapped within each of said voids, respectively, such that the two rigid contents of interest are interconnected by the connective element.

A metamaterial unit comprising:

• a matrix comprising a plurality of unit-cells;
• at least one void within at least one unit-cell of the plurality of unit-cells;
• and
• a content of interest trapped within the at least one void, wherein the content of interest is freely movable within the at least one void, thereby providing a respective unit-cell with an intended predetermined property associated with the presence of the content of interest within the at least one void, wherein the content of interest is an interlocking element, wherein the at least one void comprises one or more mating elements configured in size and shape to mate with the interlocking element upon relative movement between said interlocking element and said one or more mating elements, whereby application of a pressure beyond a predetermined threshold value on the matrix is configured to cause said relative movement to occur and thus interlock said interlocking element with said one or more mating element thereby maintaining the matrix in a deformed state even upon removal of said pressure.