The Center for Nanotechnologies and Nanomaterials of Mordovia Republic has successfully tested pastes for printing of conductive stretchable elements.
In contrast to the traditional flexible conductive materials for portable electronics, the developed paste allows to print conductive elements that can be stretched up to 200% of the original length and return to the original state while maintaining current-conducting properties. So far DuPont is the only company that produces a similar product. A few other companies have products that are in production but not yet available in the market, for example, similar product of Panasonic.
"The paste required good adhesion to the various substrate materials, the possibility of screen printing on a large surface, relatively small increase in the resistance to tensile elements and their high wear resistance," says Dmitry Korovin, an engineer at TС Printed Technologies, a project company of Mordovian Nanocenter.
The most modern inks consist of silver powder with low specific resistivity as an electrically conductive filler, that have relatively high cost and high fatigue in tension. It needs a revision of the development mechanism of electrically conductive network to reduce expensive silver content in pastes. In order to make significant changes in the conductivity of the paste, it is necessary to achieve a local distribution of the electrically conductive filler during drying.
«We transferred all known principles of self-organization to our environment, and it worked. As a result, the electrically conductive network was formed predominantly only on the surface but not over the entire area of the polymer. This allowed to reduce the precious metal content, therefore, reduce the cost of the final product», said Dmitry Korovin.
The paste has a low cost, allows printing on various types of elastic substrates that can be dried at temperatures up to 200 ° C. Silver-containing material is applicable in electronics for sportswear and uniforms with biometric sensors, as well as in industry for pressure, deformation and humidity sensors.
Nowadays, work is underway to optimize the composition of the paste and apply for a patent. The company plans to involve new partners for development of ready-made solutions for portable electronics.