Positive and negative poisson ratio material

A material, comprising:

• a first characteristic direction;
• a second characteristic direction substantially perpendicular to the first characteristic direction;
• a third characteristic direction having an angle of about 45 degrees with the first characteristic direction;
• a plurality of first films formed from a plurality of carbon nanotubes aligned in the first characteristic direction;
• a plurality of second films formed from a plurality of carbon nanotubes aligned in the second characteristic direction;
• wherein the first films and the second films are alternately arranged and stacked on one another and the carbon nanotubes in the first films are substantially perpendicular to the carbon nanotubes in the second films;
• the material shows a negative Poisson's ratio when it is stretched or compressed in the first characteristic direction or the second characteristic direction, and the Poisson's ratio material shows a positive Poisson's ratio when it is stretched or compressed in the third characteristic direction.