A team of researchers at the State University of New York at Binghamton have created a prototype circuit board that is made of a sheet paper with fully integrated electrical components, that can be burned or left to degrade.
Most small electronic devices contain circuit boards that are made from glass fibers, resins and metal wiring, which are not easy to recycle. One alternative is to use paper-based circuit boards, which should be easier to dispose of, less expensive and more flexible. However, current options require specialised paper, or they have traditional metal circuitry components mounted onto a sheet of paper.
Prof. Seokheun Choi and his colleagues wanted to develop circuitry that would be simple to manufacture and that had all the electronic components fully integrated into the sheet.
They designed a paper-based amplifier-type circuit that incorporated resistors, capacitors and a transistor, by first using wax to print channels onto a sheet of paper in a simple pattern. After melting the wax so that it soaked into the paper, the team printed semi-conductive and conductive inks, which soaked into the areas not blocked by wax. Then, the researchers screen-printed additional conductive metal components and casted a gel-based electrolyte onto the sheet.
Tests confirmed that the resistor, capacitor and transistor designs performed properly. The final circuit was very flexible and thin, just like paper, even after adding the components. To demonstrate the degradability of the circuit, the team showed that the entire unit quickly burned to ash after being lit on fire. The researchers say this represents a step toward producing completely disposable electronic devices.
source: Eurekalert