Multiple conductivity states have been reported for a number of years in polymeric systems, but they have only begun to gain importance recently with the growing interest in the memristor. The memristor is a passive, two terminal electrical component that changes its conductivity based on its previous exposure to electric currents that was originally conceived to relate electric charge and magnetic flux linkage. The polymer 2-(9H-carbazol-9-yl)ethyl methacrylate (PMAK) is one such polymer that has been made into a device that shows a change in the resistance after the application of a certain voltage. This bistability has been shown to be caused by a conformational change in the polymer under an electric field. As a voltage is applied to the material, the electro active carbazole moieties are able to realign themselves into a confirmation that allows for the material to more efficiently transfer charge. Thus, the material is able to switch from a low conductivity "OFF" state to a high conductivity "ON" state. By further increasing the chain length that binds the carbazole to the polymer backbone, the chain flexibility will increase and lower the polymers glass transition. This increase in chain flexibility has a very complex relationship with the polymers ability to undergo conformational change and its properties as a memristor. Through this basic tenet of polymer structure properties, these methacrylate polymer systems can be altered to control the polymer flexibility and how it functions as a memristor. In this research, methacrylate based polymers containing carbazole moieties were synthesized via free radical copolymerization of methacrylate monomers containing the respective functional group. Variations to the lengths of the side chains that are attached to the carbazole moiety to the polymer backbone were studied for their effects on the electrical properties of these polymeric devices.

Rational design of methacrylate polymers with pendant carbazole moieties for use as memristors

254th National Meeting (2017)

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