Surface Modification of Diatomaceous Earth Particles Improves Storage and Release of Organic Corrosion Inhibitors in Coatings

Recent research has shown the potential of diatomaceous earth (DE) as an efficient and environmentally friendly storage system for active chemicals such as corrosion inhibitors in coatings. However, the storage of organic inhibitors is challenging due to their low solubility and reactivity with the coating matrix. To address this challenge, researchers at Delft University of Technology studied the effect of surface modification of DE particles on the loading and release of organic corrosion inhibitors in solution and from coatings. The study found that surface modification with a mid-length silane (C8) adsorbed 3.5 times more inhibitor without affecting release kinetics, and improved particle dispersion and protection of the inhibitor in coatings.

Key Takeaways:

• Surface modification of diatomaceous earth (DE) particles with trichlorosilanes improved the loading and release of organic corrosion inhibitors in solution and from coatings.
• The mid-length silane (C8) adsorbed 3.5 times more inhibitor without affecting release kinetics.
• Surface modification improved particle dispersion and protection of the inhibitor in coatings, preventing unwanted side reactions.
• The study demonstrated high levels of corrosion protection and the formation of stable protective layers at damaged sites using in-situ reflected microscopy and postmortem analysis.
• The research opens the path to more efficient use of functional DE particles in coatings.
• Jingjing Zhao and other researchers at Delft University of Technology conducted the study, which was published in NPG Asia Materials in 2025.
• The research focused on using 2,5-dimercapto-1,3,4-thiadiazolate di-potassium salts (KDMTD) as a model corrosion inhibitor for its high solubility and effectiveness in protecting Cu-rich aerospace alloys.
• Santiago J. Garcia and Dong-Hyuk Na were also authors of the research.

Statistics:

• DE particles were modified with three trichlorosilanes with varying alkyl chain lengths (C4, C8, C18).
• UV-Vis spectroscopy revealed a relationship between chain length and inhibitor loading and release, with mid-length silane (C8) adsorbing 3.5 times more inhibitor.
• In-situ reflected microscopy during immersion and postmortem analysis of damaged coatings demonstrated high levels of corrosion protection and the formation of stable protective layers at damaged sites.

Sources:

• Surface modification of natural porous silica microparticles to control the loading and release of organic corrosion inhibitors in coatings. NPG Asia Materials, 2025, 17(1):1-18.
• Nature Portfolio.
• doi: 10.1038/s41427-025-00608-5