Auxetics Auxetics

What Are Their Characteristics?What Are Their Characteristics? Auxetic materials are Auxetic materials are

any material that any material that thickens when thickens when stretched and Thins stretched and Thins when compressed.when compressed.

Known as “a negative Known as “a negative Poisson’s Ratio, ”Poisson’s Ratio, ”

They have both high They have both high energy absorption and energy absorption and fracture resistance.fracture resistance.

Low density to allow Low density to allow for the pinched areasfor the pinched areas

1V

Natural Occurring Natural Occurring

single-crystal arsenic single-crystal arsenic catskincatskin load-bearing cancellous bone from load-bearing cancellous bone from

human shinshuman shins

Current UsesCurrent Uses

Pyrolytic graphite for thermal Pyrolytic graphite for thermal protection in aerospace applications.protection in aerospace applications.

Ni3Al in vanes for aircraft gas Ni3Al in vanes for aircraft gas turbine engines.turbine engines.

Expanded form of PTFE used to make Expanded form of PTFE used to make Gore-Tex.Gore-Tex.

Foam mopsFoam mops

Continued Current UsesContinued Current Uses

polymeric and metallic foamspolymeric and metallic foams carbon fibre composite laminatescarbon fibre composite laminates microporous polymersmicroporous polymers

Possible UsesPossible Uses

Biomedical-Biomedical-Prosthetic materials, surgical implants, Prosthetic materials, surgical implants,

suture/muscle/ligament anchors and suture/muscle/ligament anchors and a dilator.a dilator.

Filters-Filters-Any foam or honeycomb filter is a Any foam or honeycomb filter is a

possibility.possibility. Fibers-Fibers-Bullet proof vests.Bullet proof vests.