Light-dependent advanced material discovered

Researchers from the Queensland University of Technology (QUT) have discovered a material with reversibly changing properties that could be used in 3D printing and manufacturing.

In collaboration with scientists from Ghent University (Belgium) and Karlsruhe Institute of Technology (Germany), the team have created a reprogrammable material using green LED light and darkness as the switches to change the material’s polymer structure.

The material is made from inexpensive chemical compounds including naphthalene, which is used in moth repellents.

The researchers have suggested that the material could be used as a 3D printing ink to print temporary, easy to remove scaffolds.

While the green LED light is shone on the material is remained stable and strong, when the material is darkness, the material began to break up and become soft and liquefied. The brightness of the light could modulate the mechanical properties of the material.

The next step for this research is looking at other chemical combinations can achieve the same result.

According to professor Christopher Barner-Kowollik, what is revelatory about this research is the use of light to stabilise the bonds within the material, leading to the development of a new term, light-stabilised dynamic materials (LSDMs).

“We are hoping to introduce LSDMs as a whole new class of materials,” said Barner-Kowollik.

In other processes, light, heat or chemicals are used to break up polymer molecule chains, while this research inverted this to use light to strengthen the bonds.

“This is what you call an out-of-equilibrium chemical system. The constant energy of the green light keeps the chemical system in this bonded form, pushing it out of its equilibrium. Take away the light, and the system goes back to its relaxed, lowest energy state,” said Barner-Kowollik.

This research could be applied in the field of 3D printing as a scaffold that can support the polymer printing process and then be removed.

“With a light-stabilised dynamic ink used as a scaffold you could 3D print under light, then switch the light off to let the scaffold ink flow away,” said Barner-Kowollik.