Jaeshin Kim

A redox-responsive polymer-modified indium tin oxide (ITO) was fabricated via a convenient filter paper-assisted Cu⁰-mediated surface-initiated atom transfer radical polymerization (FP-Cu⁰-SI-ATRP), enabling the formation of ferrocene-containing polymer brushes, poly­(2-(methacryloyloxy)­ethyl ferrocenecarboxylate) (PFcMA), with tunable thickness on ITO. By varying the monomer concentration, uniform polymer brushes with controllable thicknesses ranging from 10 to 122 nm were obtained. Compared to surface-initiated atom transfer radical polymerization (SI-ATRP), FP-Cu⁰-SI-ATRP achieved significantly higher polymerization rates, thicker films, and a shorter reaction time (5 h vs 20 h), while eliminating the need for subsequent metal catalyst removal. Characterization by Fourier Transform Infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV–vis), atomic force microscopy (AFM), an ellipsometer, and water contact angle (WCA) measurements confirmed the successful grafting and systematic changes in PFcMA brush thickness and surface properties. Electrochemical performance, assessed by cyclic voltammetry (CV), revealed that thinner films exhibited efficient, diffusion-controlled redox behavior, whereas thicker films showed increased resistive effects. While the modified ITO prepared via SI-ATRP displayed lower redox activity despite having a similar thickness, this suggests a less favorable polymer brush morphology for charge transport. These findings establish FP-Cu⁰-SI-ATRP as a promising approach for constructing redox-active interfaces with tunable electrochemical properties for smart material applications.

Porous organic cobaltocenium‐containing particles are scarce in literature but highly interesting for their electrochemical properties and reusability in, for example, catalysis or magnetic systems. In this work, we present a scalable one‐pot strategy to introduce tailorable amounts of cobaltocenium on a porous substrate, adjusting the electrochemical switching capability. For this purpose, 3‐(triethoxysilyl)propan‐1‐amine (APTES) and ethynyl cobaltocenium hexafluorophosphate is used as functionalization agents for in‐situ catalyst‐free hydroamination, followed by silane condensation at the particles’ surface. Functionalized particles are characterized by attenuated total reflection infrared spectroscopy (ATR‐IR), thermogravimetric analysis (TGA), laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDS), inductively coupled plasma mass spectrometry (ICP‐MS), powder X‐ray diffraction (PXRD) and cyclic voltammetry (CV) showing excellent control over the degree of functionalization, i. e., the added cobaltocenium reagents. The electrochemical stability and good addressability while preserving the porous structure are shown. By utilizing higher amounts of APTES, the overall cobaltocenium amount can be reduced in favor of additional amine groups, strongly affecting the electrochemical behavior, making this functionalization strategy a good platform for metallopolymer immobilization and tailored functionalization. Additionally, thermal treatment of the synthesized metallopolymer microparticles paves the way to magnetic properties with tailorable microporous architectures for end‐of‐life and upcycling aspects.