MSU Technologies

Materials with a colorimetric memory response to compression

VALUE PROPOSITION
The ability to detect compression-based end-of-life for materials is important in any application where foam padding is used. There is a need to determine if padding is performing to specification. There is no simple way to determine when foam materials have degraded to the point of being no longer useful. The degradation of such materials occurs by loss of resiliency, but there is no rapid, on-site means of gauging such degradation. This technology will lead to incorporation of microcapsules into foam padding that will burst when exposed to excessive force, releasing their contents and changing the color of the foam. Anticipated use for this technology includes shoe insole lifetime determination, fitting of prosthetics, and evaluating when multiple-use packing material has reached the end of its useful lifetime.

DESCRIPTION OF TECHNOLOGY

Silica microvessels that contain a dye solution are incorporated into the foam material. When initially formed the resiliency of the foam prevents the microvessels from being exposed to sufficient force to cause breakage. As the foam ages and its resiliency is diminished, the microvessels are exposed to forces sufficient to cause microvessel breakage, which releases their colored contents. Degradation of the foam is thus seen as a change in its color when it has reached the end of its useful lifetime. Typical padding is made from Thermoplastic Urethane (TPU) and Vinyl Nitrile Foam. Different types of polymers may be included with varying degrees of durability, shock absorption and comfort level. This technology introduces materials that cause the padding to change color when they are subjected to pressure that exceeds the pre-determined level. The color change is irreversible, allowing simple visual inspection to determine if the foam padding is at the end of its functional lifetime.

BENEFITS