Chemical Addition of Octadecane (C18) to 3D-Printed Parts for Surface Activation with Example Applications

3D-printing has experienced rapid growth in both research and industry due to its ability to quickly prototype intricate structures, utilize standardized and sharable CAD files, and enable customizable fabrication. While modern 3D printers allow for easy customization of geometry and dimensions, the limited number of options for modifying the surface chemistry of 3D-printed parts restricts the full potential of this technology. In this work, we present an accessible chemical protocol for functionalizing 3D-printed surfaces with octadecane (C18), a commonly used stationary phase in chromatography. This functionalization serves as a versatile platform, enabling strong retention of a wide range of molecules on 3D-printed surfaces via partitioning, thus chemically activating the surface. Thorough quantitative characterizations confirmed the effectiveness of this approach. To demonstrate new opportunities that can be unlocked by the C18-functionalized 3D-printed parts, we showcased applications including protein and enzyme immobilization for sensing, customized solid-phase extraction probes, drug loading and release, and the retention of an antiseptic reagent for effective bacteria elimination in a leaching-free manner. This study substantially enhances the potential of 3D-printing by enabling surface chemistry customization alongside traditional shape customization, thereby promoting future discoveries and innovations.