Researchers from the University of Melbourne have engineered a new 3D printed gel that can heal itself, and change form in response to environments.
The self-healing gel has various applications, from fixing cracked phone screens to adaptive camouflage to car exteriors.
The chemical engineering experts say their 3D printed self-healing gel 'regenerates' after being cut.
According to Dr Luke Connal, a researcher at the Melbourne School of Engineering, 3D printers have thus far been limited by the range of materials that they can print.
To help rectify this, his team has developed a polymer-based ‘ink’ that can self-heal, and which can change shape over time.
The gel-like ink is made from a polymer known as poly (hydroxyl ethyl methacrylate), which is the base polymer for many types of contact lenses. It starts off similar in texture to toothpaste. When pressure is applied, it will flow, and when the pressure is removed, it becomes stable again.
“After printing, these objects can heal a crack or even a cut and regain their original strength,” Dr Connal explains.
“This could enable custom printing of coatings that can heal after breakages, potentially as coatings for mobile phones.”
The materials can also change shape when triggered by a solvent, such as water. This means that 3D printed objects can be prompted to change shape.
The healing process is based on dynamic covalent chemistry, where chemical bonds are formed, broken and reformed in a controlled and triggered manner. This means the polymer gel is strengthened, but can be weakened when exposed to a stimulus, such as pressure or acidity. By making use of this weakening, it is possible re-form the material to perform feats such as healing cracks.
The goal is to develop selective coatings for high-end products that are subject to stress, such as mobile phones, hand held devices and car surfaces. When cut or cracked, the application of slight heat will allow them to self-heal.
These self-healing ‘smart’ objects could also change their shape upon sensing their chemical environment.
The next step is investigating how to increase the materials’ strength and flexibility and even ability to change colour, possibly allowing the development of chameleon-like technology such as for camouflage.