Polymer Technology Continues to Advance

A research project carried out by the Adolphe Markle Institute (AMI) and Japan's Hokkaido University has resulted in a new method to specifically tailor the properties of stress-indicating molecules. Such molecules can be integrated into polymers and are used to give a visual signal of damage or excessive mechanical loads.

The current approach is based on specifically-designed sensor molecules, the weak chemical bonds of which break when applied force exceeds given threshold. When these bonds are broken, a visual effect such as a colour-change signals that the threshold has been broken. A fundamental limitation of the technology is that the bonds can also break on exposure to heat or light, giving a false-positive response.

This lack of specificity has, in the past, reduced the practical value of stress-indicating polymers and usually makes the effect irreversible. In response to this issue, the research team has developed a new type of sensor molecule that will only activate by mechanical force and, unlike previous force-transducing molecules, there is no breaking of chemical bonds.

Instead, the newly developed sensors comprise two mechanically interlocked parts. This interconnection prevents to two parts from actually separating, while still permitting them to be pushed together or pulled apart.

Professor Christoph Weder, Chair of Polymer Chemistry and Materials at AMI, said: “The design approach allows one to tailor the properties of such sensor molecules, as their behaviour is quite predictable. We chose to demonstrate this by tackling materials the display white fluorescence when stretched."

Information in this article taken from https://­www.­british­plastics.­co.­uk/­materials/­researchers-find-new-type-of-sensor-molecule-for-polymers-to/

16th June 2019, 16:18