Chemists and engineers joined hands and used XNUMXD printing to make XNUMXD objects with innovative capabilities. For example, the scientists created a plastic plate that turns purple in response to stretching - a mechanism that offers a simple way to record the force exerted on an object.
![The upper plate is a plastic plate prepared with the help of XNUMXD printing that carries inside it the letters "UW" printed in a slightly different material. The lower plate shows the plate after being stretched. [Courtesy of AJ Boydston/UW]](https://www.hayadan.org.il/images/content3/2015/02/two_ws-500x386.jpg)
[Translation by Dr. Nachmani Moshe]
Imagine printing molecules that could respond to their environment. Chemists and engineers joined hands and used XNUMXD printing to make XNUMXD objects with innovative capabilities. For example, the scientists created a plastic plate that turns purple in response to stretching - a mechanism that offers a simple way to record the force exerted on an object.
A research project conducted at the University of Washington merges normal chemistry with XNUMXD printing - the scientists created a plastic plate in the shape of a bone that turns purple in response to stretching, a mechanism that offers a simple way to record the force exerted on some bone. "Here at the University of Washington, this is a merger that has been waiting for its time - XNUMXD printing from the engineers and functional materials from the chemists," said Andrew J. Boydston, professor of chemistry at the university, lead author of a paper detailing the findings and published in the scientific journal Applied Materials. and Interfaces.
The chemists created a plastic polymer consisting of many repeating units tightly joined together that is fed into a commercial XNUMXD printer located in the university's chemistry lab. One of the printer cartridges contained the material poly-caprolactone, a material similar to what a XNUMXD printing company markets as 'flexible sheeting'. The second cartridge contained a plastic material into which the spiro-pyran molecule was incorporated, which changes color when stretched. "We wanted to demonstrate that functional chemistry can be easily incorporated into materials that are already printable today," said the lead researcher. "We found that tailored chemistry can be easily incorporated into XNUMXD printing."
The printed plate is a piece of white plastic inside which there are almost invisible stripes that turn purple in response to the force applied to the plate. The plate functions as a cheap mechanical detector that does not include electronic parts. The device itself can be printed in 15 minutes from materials that cost less than one dollar. It would be possible to use a detector of this type to record the forces or pressures exerted on a building or on other structures. The researchers are interested in developing a detector that can also record the speed of the force (impact), for example, inside a football helmet that can change its color when it is hit by a strong enough force.
Different design instructions can cause the printer to print the plastic components in many configurations - when the color-changing material is in stripes in the center of the part, in other areas and in different shapes. The XNUMXD printing technology offers new capabilities, says the lead researcher, for example, for the development of personalized medical implants or other structures that include materials that react to their environment.
