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.