Molecularly imprinted polymers (MIPs) function as a synthetic analogue to antibody-antigen systems with a “lock and key” mechanism for molecular recognition. The combination of MIPs and electrochemical interfaces provide a promising sensing platform for environmental contaminant (e.g., per- and polyfluoroalkyl substances, PFAS) that is a cost-effective, rapid, and portable alternative to laboratory-based analytical methods. While MIP-based sensors have been shown to provide sufficient limit of detection to common PFAS, remaining challenges arise from the degradation of the selective binding sites over multiple cycles, which limits reliability and reusability of the sensors. In this presentation, we present our progress toward understanding the relationships among the electropolymerization, the physical morphologies, mechanical robustness, and sensing properties of MIP films based on poly(ortho-phenylenediamine) (PoPD). Specifically, by identifying key fabrication parameters, we demonstrate the ability to improve the elastic recovery and reversibility of selective binding events as determined by AFM-based nanoindentation and electrochemical analyses. Furthermore, we will discuss our nanoscale characterization of the spatial distribution of selective binding sites using spectroscopic techniques to help develop fundamental insights into the influence of diffusion boundary layers during the electropolymerization. We anticipate that our results will provide a deeper understanding of how to modulate the mechanical and sensing properties of MIP-based sensors and lead to design rules for the development of robust and field-deployable sensors for environmental analytes.
