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

A brand new 3D printing technique developed by engineers on the College of California San Diego is so easy that it makes use of a polymer ink and salt water resolution 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 resolution often called poly(N-isopropylacrylamide), or PNIPAM for brief. When this PNIPAM ink is extruded by means of a needle right into a calcium chloride salt resolution, 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 referred to as the salting-out impact, the place the salt ions draw water molecules out of the polymer resolution attributable to their robust attraction to water. This removing of water causes the hydrophobic polymer chains within the PNIPAM ink to densely mixture, making a stable type.

“That is all achieved beneath ambient situations, without having for added steps, specialised tools, poisonous chemical substances, warmth or stress,” mentioned research 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 easy interplay between PNIPAM and salt water at room temperature to realize the identical end result, however with out the environmental value.

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

To reveal the flexibility of their technique, the researchers printed buildings out of PNIPAM inks containing different supplies. For instance, they printed {an electrical} circuit utilizing an ink made from PNIPAM blended with carbon nanotubes, which efficiently powered a light-weight bulb. This printed circuit may be dissolved in contemporary water, showcasing the potential for creating water-soluble and recyclable digital parts.

Bae and her workforce envision that this straightforward and reversible 3D printing method may contribute to the event of environmentally pleasant polymer manufacturing applied sciences.