Microstructured time dependent indicators

Abstract

The invention provides an article (20) comprising a substrate (1) having a micro-structured surface that defines a plurality of channels (4) and a fluid that is separated from the substrate until activation of the article is desired, wherein the article is designed such that it can be activated at a desired point in time to allow contact of the fluid with at least one of the channels of the substrate, said article being adapted for providing a measurable variable electrical characteristic, said variability being in correspondence with the progress of the fluid as it migrates through the channels of the substrate.

Description

technical field [0001] The present invention provides time-related indicators, including but not limited to chronographs and time / temperature indicators. Background technique [0002] An easy way to provide an indication of when the expiration date on perishable products has expired is to stamp each product with a suggested date by which the product should be used. However, a disadvantage of this approach is that the actual shelf life of a perishable product depends on the temperature history to which the product is exposed, since the rate of spoilage of perishable products generally increases with increasing temperature. That is, perishable products have a shorter remaining shelf life after exposure to relatively higher temperatures for a certain period of time than after exposure to relatively lower temperatures for a certain period of time. More broadly, the rate at which a specific property or characteristic of any substance or product may change increases with increasi...

AI Technical Summary

Problems solved by technology

However, actual exposure conditions can never be predicted or controlled, hence the need for time-temperature indicators

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