Researchers have developed a self-healing rubber that is designed for light 3D printing and can have varying levels of hardness.
Everyone has encountered problems due to a flat tire or cracked soles in shoes, after which they become unusable. A team from the UC Viterbi School of Engineering has developed a 3D printed rubber material that can self-repair its structure.
The production technology is based on photopolymerization – the process of hardening a liquid resin under the influence of light, achieved through the use of thiols. When an oxidizing agent is added to a chemical mixture, thiols are converted to disulfides, a group of chemicals that are capable of self-healing..
However, an increase in the proportion of the oxidizing agent leads not only to an improvement «healing», but also to the weakening of photopolymerization. Therefore, the researchers settled on the optimal ratio, which provides quick adhesion and fast hardening. As a result, it takes only 5 seconds to print a 17.5 mm square, and about 20 minutes to make whole items..
The recovery rate lasts on average several hours and depends on the temperature of the material. The optimal conditions are considered to be a range of 40 °C up to 60 °C, while the structure can be restored almost 100%. The process also proceeds at room temperature, but takes longer.
Researchers used the developed technology to create a shoe sole, an element of soft robotics, a multiphase composite and an electronic sensor. They are currently exploring ways to change material stiffness levels to expand its scope..
We also previously reported that scientists from nine research institutes have created an extremely lightweight ceramic material that able to withstand strong heat, huge temperature fluctuations and is highly flexible.
text: Ilya Bauer, photo: University of Southern California Viterbi School of Engineering
Oxidizing Agents and Reducing Agents