American engineers have invented a simple method of high-precision three-dimensional printing, suitable for the construction of microelectronics. It is based on the formation of the skeleton, different parts of which have electrical charge, then the applied material sticks to the oppositely charged sites. Using this method, you can create a three-dimensional electrical circuits of any complexity, in particular, tactile sensors and sensors form. Article published in the journal Nature Electronics.
Three-dimensional printing has established a reputation as a simple and cheap method of production. However, when it comes to unusual shapes, microscopic or large quantities of materials — there are problems which restrict the printing of complex objects. For example, simultaneous printing of plastic and metal still have not found a wide industrial application.
Long before the term “3D printing” in the production of chips used microlithography essentially the same print. Processors are created in layers, and the application of each layer of material depends on the shape of the mask was preexpansion on the photosensitive film. Roughly speaking, it projected the image of a maze of contacts and unexposed areas were washed away, and on the basis of the resulting frame was built, the conductive circuit. Then again deposited film again exhibited, and so the cycle repeated many times, until there was the desired three-dimensional structure.
Ryan Hensley (Ryan Hensleigh) and his colleagues from the University of California in Los Angeles decided on the basis of photolithography to create an entirely new method of creating three-dimensional objects. A significant limitation of the traditional technology was her plane because of plane figures difficult to create complex three-dimensional structure. Engineers figured out how to work with the polymer frame is in layers and all at once.
They decided to use the property of opposite charges attracting each other. For the production of new technologies need baths with three different plastics. In addition to the neutral, the other two give electric charge — positive and negative. The basis for the future frame is placed in a bath with one of the plastics, and exhibit a notched mask, then removed, dried, and in the other tub Shine a different pattern. This creates a three-dimensional lattice, the bulk of which are neutral, and some point — loaded.
After that all that remains is to dip the frame into the liquid with the diluted material should be applied, for example, copper. The material is also made in such a way that he had the charge, which he deposited from water in oppositely charged sites of the lattice. The result is a three-dimensional structure in which plastic and metal twisted arbitrarily difficult.