This new, very clever heat-activated material can remember hundreds of earlier shapes by memory. It is able to reset its memory and change shape under high temperature and could lead to a new generation of reusable, self-folding materials with applications ranging from electronics to medical devices.
This new material is classified as a shape memory polymers. Shape memory polymers are materials are defined as materials that revert to or rather ‘remember’ their original form and can return to it when exposed to a particular temperature change, magnetic field or electrical charge, for example.
Shape memory material are nothing new, however shape memory polymers have only been able to remember a few shapes up until now. These so-called ‘first-generation’ shape polymers relied on their material elasticity. When cool, the string-like polymers coil up. When heated, they straighten out into a new shape and then revert back to the default shape once cool again. In this way, they are considered to have a ‘memory’of their original shape.
What is different about this new ‘second-generation’ shape polymer however is that it is both elastic and plastic. Developed by material scientists at Zhejiang University in Hangzhou, they have developed a carbon crosslinked polymer made of polycaprolactone (PCL). When temperatures are below 70C, the material is elastic and can be temporarily deformed. Once it warms up again, it reverts to its original shape. Then, when heated to a much higher temperature (above 130C) , the actual memory of the material can be changed.
This means that numerous changes to the material’s shape can be made, with the changes ‘saved’along the way. Tests show that the material can memorie and shift between hundreds of different shapes without showing any signs of stress or fatigue.
The full scientific paper and source on this innovation can be found here