First 4D-printed, shape-changing ‘seed robot’ to monitor the environment

Researchers in Italy have developed a new 4D-printed soft robot that can change shape according to humidity changes and navigate in the soil. This device could be a great way to monitor the environment.

The process of 4D printing involves using 3D printers to create objects whose shape or properties can be altered in response to external factors, such as temperature and light. The technology has previously been used to create programmable, self-assembling material technologies.

A soft robot that can analyze soil has been created using 4D technology. The seed structure of South African Geranium was used as inspiration.Pelargonium appendiculatumThe first biomimetic seed robot was created by researchers at Genova’s Istituto Italiano di Tecnologia.

“Our studies started from the observation of nature, with the aim to imitate the strategies of living beings or their structures and replicate them in robotic technologies with low environmental impact in terms of energy and pollution,” said Barbara Mazzolai, corresponding author of the study.

Geranium seeds, and other members of the Gerianaceae flowering plant family, can take advantage of their hygroscopic properties (activated by humidity) by detaching under the right conditions. They then change shape, and can penetrate the soil on their own. This increases the chances of germination.

Researchers used a combination 3D printing and Electrospinning to replicate the structure and biomechanics in the natural seed. Electrospinning uses an electric force to bring charged polymers into fiber diameters in the range of 100 nanometers.

Researchers used fused deposition modelling (FDM) for printing a layer of substrate made from polycaprolactone, a biodegradable polyester thermoplastic. The oxygen plasma was used to activate the PCL to make it water-attracting. They then added electrospun fibers with hygroscopic properties, consisting of a polyethylene-oxide shell and a core made from cellulose nanocrystals to the substrate.

The soft robot was tested on a soil sample. It adapted its shape in order to interact with the roughness and cracks. It was highly energy efficient, and it could lift 100 times more than its weight.

The below video produced by Istituto Italieno di Tecnologia shows how the robot seed reacted to the soil when tested.

Researchers say that the novel device is a way to monitor the planet in a non-intrusive manner.

“With this latest research, we have further proved that it is possible to create innovative solutions that not only have the objective of monitoring the well-being of our planet, but that do so without altering it,” Mazzolai said.

The researchers are hopeful that the device’s low cost, simple design and data-collecting capabilities will be particularly useful in remote areas.

“These biodegradable and energy-autonomous robots will be used as wireless, battery-free tools for surface soil exploration and monitoring,” said Luca Cecchini, first author of the study. “This bioinspired approach has allowed us to create low-cost instruments that can be used to collect in-situ data with high spatial and temporal resolution, especially in remote areas where no monitoring data are available.”

The study was published by the journal Advanced Science.

Source: Istituto Italiano di Tecnologia