Incorporation of non-conjugated polymer chain in conjugated polymer matrix: A new single step strategy for free standing non-volatile polymer memory

A new single step strategy for polymer memory materials has been explored using freestanding polypyrrole (PPy) film in which non-conjugated polymer chains are incorporated as trap states during synthesis. The PPy film was synthesized by the acidic oxidation of 2,2':5',2 ''-terpyrrole at the air/water interface. The free-standing PPy films show large hysteresis along with current peaks in opposite directions during current voltage (I-V) characteristics. Hysteric behavior has been utilized to show rewritable memory effect. Furthermore, once electrical state (high or low conduction state) is set, the state is stable for months in ambient condition unless the state is reset by applying a voltage of opposite polarity. Thus the PPy film can be used as read once memory. The memory effect of the film is due to the conformational changes of non-conjugated polymer chains in the PPy matrix. The changes in conformation were confirmed from UV-Vis and FTIR spectra. This new strategy leads free-standing film based all organic polymer memory devices at ultra low cost. (C) 2013 Elsevier B. V. All rights reserved.