Conformational Transitions of Polymer Brushes for Reversibly Switching Graphene Transistors

We developed a facile, but efficient, approach to graphene field-effect transistors (FET) functionalized with polymer brushes, in which the conductance can be reversibly switched by solvent-induced polymer conformational changes. Our experimental and stimulation results demonstrated that the solvent-induced conformational transition of the polymer brush could affect the carrier concentration by changing the number of scattering sites associated with the graphene−polymer contact areas, leading to reversible electrical switching for the graphene FET device. Both end-adsorbed diblock and triblock copolymers showed similar switching effect through the solvent-induced chain stretching−collapse and tail-to-loop conformational changes, respectively. This work provides new platform technologies for developing novel electronic devices with tunable electrical properties and for studying macromolecular conformations and conformational transitions.