60 seconds on...a silk sensor

Materials World magazine
30 Apr 2017

What is it? 

A nanoscale probe, known as a mechanophore and made from the dye rhodamine spirolactam, implanted into a lightweight composite. The composite is made of epoxy and silk filaments using Bombyx mori silkworms.

Who is involved? 

Researchers from the National Institute of Standards and Technology (NIST), USA, led by Dr Jeffrey Gilman. The paper, entitled Observation of Interfacial Damage in a Silk-Epoxy Composite, Using a Simple Mechanoresponsive Fluorescent Probe, was published in the journal Advanced Materials Interfaces. Professor Fritz Vollrath’s team at the University of Oxford, UK, prepared the silk fibres. 

How is it novel?

The rhodamine spirolactam dye, implanted into the silk fibres of the composite, changes state, from dark to light, when a force is applied. A laser focused on the composite causes it to fluoresce. This change of state is only visible using a red laser and a microscope designed by the NIST team. Using this microscope the team could see tiny breaks in the composite’s structure. Polymer composites that contain silk fibres benefit from the fibre’s added strength. By implementing the probe at the composite’s interface, the dye’s reaction to stress allows breaks to be visible. 

How can it be used?

The NIST team plans to research the possibilities of implanting the probe in other composites. They also aim to use the sensor to develop composites that can withstand extreme temperatures. The silk sensor could lead to the development of stronger, longer lasting and more reliable composites. 

To read the paper in full visit, bit.ly/2oxM7JZ