Scientists at the Lawrence Berkeley National Laboratory (LBNL) have found a way to "print" narrow tubes of water within liquid-state silicone oil. Because of a special nanoscale coating, the water structures survive without breaking down into droplets even as the encapsulating fluid changes shape. This new form of 3D printing could give rise to flexible and stretchable liquid electronics, aid chemical synthesis, or serve as a transport and delivery system for nanoscale particles.

The team of researchers led by Tom Russell modified a standard 3D printer so it would inject narrow streams of water directly into a small container filled with silicone oil. The streams of water don't break down into droplets thanks to a special nanoscale surfactant – a substance that reduces surface tension – which separates the water from the surrounding liquid.

The surfactant, a "nanoparticle supersoap," simultaneously disperses gold nanoparticles into the water and binding polymers into the oil. After water is injected, the polymers attach to individual water molecules, forming a soap, vitrifying, and locking the water structures into place even as the surrounding oil changes shape.

Water filaments can be as narrow as 10 microns – thinner than a human hair – and several meters long. According to the researchers, the "supersoap" mechanism allows the structure to remain in place for months at a time.

Flexible and stretchable liquid-based electronics may be many years from becoming a reality, but the liquid-printing technology also opens up other interesting avenues, such as the ability to fabricate complex coatings with specific structures or advanced magnetic properties. The researchers also suggest they could manipulate the chemistry of the tubes and use them to separate molecules or route nanoscale building blocks to their destination.

The researchers describe their printing method in a paper published in the journal Advanced Materials, and in the video below.

Source: LBNL

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