Nanoparticles combine with new ways: similar to the sand carving principle is controlled by temperate

Grains of sand and nanoparticles in the eyes of ordinary people may be small particles that can barely be seen by the naked eye. But a group of scientists from the United States have been inspired by the common sand castles and sand sculptures of the sea to create a new way of combining nanoparticles.
The study, from North Carolina state university and the university of North Carolina at chapel hill, found that magnetic nanoparticles can wrap themselves in an oil “coat”. It can be combined with unique capillary “Bridges” to form a specific chain of nanoparticles. These chains are extremely sensitive to temperature: when the temperature drops from 45 degrees Celsius to 15 degrees Celsius, the chains between these nanoparticles become brittle and then break, and the nanoparticles disperse. And if you raise the temperature again and apply some external magnetic field, these chains will magically form again.
The study was conducted by Olyn Willerf, a professor of chemical and biotics at the university of North Carolina. He says the process is like making sand castles and sand sculptures with wet sand. Adding a certain proportion of water to the sand can combine small grains of sand with a certain plasticity. The same is true of nanoparticles, which can be combined with a capillary bridge because oil and water don’t fuse. The external magnetic field can control these nano-chains, allowing them to grow in the direction scientists have envisioned.
In other words, the material can respond to changes in temperature, with some flexibility and elasticity. The technology allows for a flexible and controllable connection between the nanoparticles in the liquid, said Mr. Willerf. In the future, it is expected to develop micro-robots with flexible joints or gel with magnetic and self-healing properties.