soft robotic fingers decomposes in soil and becomes fertilizer

Moving soft robotic fingers made from plant-based materials

Researchers at the Seoul National University develop stretchable and soft robotic fingers that decompose in soil over time and act as a natural fertilizer. The body of the robotic fingers is built from polyglycerol sebacate, a synthetic elastomer made from glycerol and sebacic acid. Glycerol is a byproduct of biodiesel production while sebacic acid is derived from castor oil, and both of them are plant-based. Polyglycerol sebacate is safe since it is already used in medical implants because the body can absorb it without a toxic response.

Typical sensors and active elements of the electronic components are made of silicon, molybdenum, and magnesium, which are inorganic materials found in every smartphone and circuit board currently filling landfill sites. For the soft robotic fingers, the researchers used a class of electronics called transient inorganics, or components that are engineered to dissolve in specific conditions. The adhesive that bonds the electronic layer to the elastomer body is polyanhydride-based, a polymer class that breaks down when it comes into contact with water.

all images courtesy of the researchers at Seoul National University

devices dissolving into soil as fertilizers

To test whether or not the soft robotic fingers actually degrade over time, the researchers composted the full system, including the elastomer, adhesive, silicon, molybdenum, and magnesium, and then used that compost as soil for oat germination. The study finds that the oats grew and that the germination rates were within the range of oats grown in control soil. The silicon, molybdenum, and magnesium left behind by the decomposed electronics didn’t prevent growth, so in the end, the soft robotic fingers acted as a fertilizer.

One of the problems with new technologies is leaving a residue in the environment, which can harm it including a usual surgical robot used once in a procedure, a sensor deployed in a field to monitor soil conditions, or even a device released into a body of water to measure pH. Discarding them means these components end up in the landfill, especially when not properly recycled. With the research design, the team hopes that the objects that once lived to help humans, even saving their lives, give back to the planet by taking care of what it produces.

researchers at the Seoul National University develop stretchable and soft robotic fingers that decompose in soil

the body of the moving devices is built from plant-based materials

the researchers used electronics called transient inorganics, or components that are engineered to dissolve

view of the decomposition over time

the device can grip objects, as shown in the image

project info:

name: Biodegradable yet hyperdurable robotic fingers for zero-waste soft electronics

institution: Seoul National University | @snu.official

researchers: Kyung-Sub Kim, Jun-Seok Shim, Sung-Woo Kim, Gyeong-Seok Hwang, You-Jung Park, Joran Booth, Jae-Young Bae, Jong-hyoung Kim, Min-Ha Oh, Minseong Chae, Jooik Jeon, Ju-Yong Lee, Jae-Hwan Lee, Min-Jung Chae, Sung-Geun Choi, Young-Seo Kim, Seung-Min Lee, Se-Hun Kang, Joo-Hyeon Park, Yong-Wu Kim, Woo-Jin Lee, Im-Deok Kim, Ki-Hyun Kim, Seong-Yu Choi, Jeong-Yun Sun, Rebecca Kramer-Bottiglio, Myoung-Ryul Ok, Jae Joon Kim, Jung Keun Hyun, Kang-Sik Lee, Ju-Young Kim, Sang Yup Kim, Martin Kaltenbrunner, Seung-Kyun Kang

study: here