The science behind the effectiveness of the flag is the triboelectric effect. The triboelectric effect states that when the surfaces of two different materials touch and separate, their electrons transfer from one to the other, which builds up symbolopposite charges on the two surfaces. This reaction leads to the creation of a voltage that can drive electric current.
Professor Wang’s group already made several generators produce electricity the flag is their recent invention. The flag is made by weaving two kinds of fabric strips with the width of 1.5 centimeters and a length of 30 centimeters. They weft is a polyester textile belt with nickel coating and the warp is a copper film coated with polyimide plastic. The nickel belts are then connected together by a copper tape to form one electrode; the copper belts, on the other hand, are connected to the electrodes. The flag weighs about 15 grams, can be folded, bent and twisted.