Development of PFAS Responsive Electrolyte-Gated Field-Effect Transistors Using Conjugated Polymer-Single-Walled...

Conjugated polymers are effective dispersants of SWNTs which also impart their properties onto polymer-SWNT complexes. By modifying the polymer sidechain, the properties of the complex can be fine-tuned for targeted applications. Here, we introduced pillar[5]arenes containing pendant quaternary ammonium groups onto the polymer side chains using strain promoted azide-alkyne cycloaddition (SPAAC). The polymer effectively dispersed SWNTs, generating a polymer-SWNT dispersion in aqueous media. Analysis by ¹⁹F-NMR demonstrated that this polymer exhibits electrostatic interactions between carboxylate ions of perfluoroalkyl acids and the pendant ammonium ions. Semiconducting (sc-) enriched polymer-SWNT complexes were prepared and subsequently functionalized with the pillar[5]arene side chains. The resulting water-processable polymer-SWNT complexes were incorporated in electrolyte-gated field-effect transistor (EGFET) devices, which demonstrated strong ambipolar performance and rapid signal stabilization using DI water as the supporting electrolyte. The EGFETs were used as proof-of-concept sensors capable of detecting potassium perfluorooctanoate (PFOK) and perfluorooctanoic acid (PFOH), and differentiating them from octanoic acid as a control. This work demonstrates that preparation of functional sc-enriched polymer-SWNT complexes enables proof-of-concept sensing using EGFET devices as a model platform.