# Optimizing Electrochemical Microprinting of Conducting Polymers: Scanning Electrochemical Cell Microscopy (SECCM) Coupled with Conveyor‐Belt Surface Analysis

## TL;DR

This paper shows how SECCM can precisely print polypyrrole on various surfaces, including complex ones, using a phosphate buffer and cleaning steps.

## Contribution

The study introduces a novel SECCM strategy with phosphate buffer and cleaning steps for reproducible and patterned polypyrrole microfabrication.

## Key findings

- SECCM produces uniform, circular polypyrrole deposits on gold substrates with high reproducibility.
- Phosphate ions intercalate into the polypyrrole matrix during polymerization and can be removed via rinsing.
- Cyclic voltammetry-based SECCM enables patterning on complex surfaces like boron-doped carbon nanowalls.

## Abstract

Scanning electrochemical cell microscopy (SECCM) is a versatile tool for localized electrochemical mapping, material modification, and microfabrication. In its hopping mode, the pipette‐based system confines reactions to the meniscus contact area, allowing precise deposition control. Here, an SECCM‐driven strategy for polypyrrole (PPy) microfabrication using phosphate buffer as the electrolyte, combined with an intermediate cleaning step to remove side products and prevent pipette clogging, is reported. This approach enables the production of uniform, circular PPy deposits with high reproducibility on gold substrates. A multi‐microscopy “conveyor‐belt” analysis – combining SEM, AFM, EDX, and Raman spectroscopy – reveals that phosphate ions intercalate into the PPy matrix during polymerization, as also seen in bulk studies. This intercalation is found to be reversible via post‐deposition rinsing. Furthermore, this work demonstrates that cyclic voltammetry‐based deposition enables patterned PPy growth on complex surfaces such as boron‐doped carbon nanowalls, overcoming surface charge and wetting challenges. These findings expand the applicability of SECCM for 2D conducting polymer micro‐/nanofabrication on both flat and structurally complex substrates.

Scanning electrochemical cell microscopy (SECCM) enables precise and reproducible microprinting of polypyrrole. Using phosphate buffer and an intermediate cleaning step, it produces uniform, circular deposits, validated by a conveyor‐belt characterization workflow (SEM, AFM, EDX, Raman), revealing phosphate intercalation. Furthermore, it prints on rough boron‐doped carbon nanowalls using cyclic voltammetry, overcoming wetting/charge challenges and advancing the fabrication of micro/nanoscale sensor arrays.