Sustainable and reversible 3D printing method uses minimal ingredients and steps

A brand new 3D printing methodology developed by engineers on the College of California San Diego is so easy that it makes use of a polymer ink and salt water answer to create stable buildings. The work, printed in Nature Communications, has the potential to make supplies manufacturing extra sustainable and environmentally pleasant.

The method makes use of a liquid polymer answer referred to as poly(N-isopropylacrylamide), or PNIPAM for brief. When this PNIPAM ink is extruded via a needle right into a calcium chloride salt answer, it immediately solidifies because it makes contact with the salt water. Researchers used this course of to print stable buildings with ease.

This fast solidification is pushed by a phenomenon known as the salting-out impact, the place the salt ions draw water molecules out of the polymer answer on account of their robust attraction to water. This removing of water causes the hydrophobic polymer chains within the PNIPAM ink to densely combination, making a stable type.

“That is all carried out underneath ambient circumstances, without having for extra steps, specialised tools, poisonous chemical substances, warmth or stress,” stated examine senior creator Jinhye Bae, a professor within the Aiiso Yufeng Li Household Division of Chemical and Nano Engineering on the UC San Diego Jacobs Faculty of Engineering.

Conventional strategies for solidifying polymers usually require energy-intensive steps and harsh substances. In distinction, this new course of harnesses the straightforward interplay between PNIPAM and salt water at room temperature to attain the identical outcome, however with out the environmental value.

Plus, this course of is reversible. The stable buildings produced might be simply dissolved in contemporary water, reverting to their liquid type. This permits the PNIPAM ink to be reused for additional printing. “This provides a easy and environmentally pleasant strategy to recycling polymer supplies,” stated Bae.

To reveal the flexibility of their methodology, the researchers printed buildings out of PNIPAM inks containing different supplies. For instance, they printed {an electrical} circuit utilizing an ink manufactured from PNIPAM combined with carbon nanotubes, which efficiently powered a lightweight bulb. This printed circuit is also dissolved in contemporary water, showcasing the potential for creating water-soluble and recyclable digital parts.

Bae and her crew envision that this easy and reversible 3D printing approach may contribute to the event of environmentally pleasant polymer manufacturing applied sciences.