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N-heterocyclic carbenes (NHCs) bind strongly to metals and can be used to form stable, dense, and uniform monolayers

Background

Coatings are commonly applied to metals to:

1. alter surface reactivity to prevent corrosion and oxidation,
2. improve surface mechanical properties to minimize wear,
3. protect defined surfaces from subsequent treatments, and
4. functionalize the surface so that it can form bonds with other chemical species.

In most cases, a coating depends on physical forces to adhere to the metal. These relatively weak forces often result in delamination of the coating from the metal surface, leaving the unprotected metal exposed. A better approach would be to utilize strong chemical bonds to adhere the coating to the metal substrate. Such bonding can be formed with N-heterocyclic carbenes (NHCs), a class of organic molecules known to bind strongly to a variety of metals.

Recently, the Carbon to Metal Coating Institute (C2MCI) at ºÚÁϳԹÏ×ÊÔ´ was established to advance the science behind NHC-based coatings and to develop commercial applications in the corrosion protection, semiconductor manufacturing, and surface functionalization fields. Consisting of over 45 researchers from universities around the world, the C2MCI is leading the development of these novel NHC-based coatings.

Technology Overview

NHCs are well-known organic molecules whose structures can be varied to produce a variety of distinct NHCs. NHCs are most commonly known to be useful as ligands in organometallic chemistry, however, C2MCI researchers have discovered that they can form ultra-stable monolayers on a variety of metal surfaces, which has generated significant interest in developing NHC-based coatings to protect and functionalize metal surfaces. These organic materials are also known to remove oxide prior to deposition. Potential applications are as follows:

The utility of these coatings in corrosion protection, either on their own as a monolayer or as a primer that ‘anchors’ existing topcoats, has recently been demonstrated by researchers at the C2MCI. Corrosion tests on NHC-coated mild steel in 3.5 wt % NaCl revealed the potential of NHC monolayers to be protective due to the observed decrease in corrosion after NHC deposition. Investigations on the use of an NHC as a primer with epoxy, polyester, and polyurethane-based topcoats are ongoing.

NHCs have also been identified as effective small molecule inhibitors (SMI) in area-selective atomic layer deposition and, as such, may find use in the semiconductor industry. C2MCI researchers have shown that NHCs demonstrate a preference for adsorbing onto metal surfaces over dielectric materials and enable the selective deposition of insulating dielectrics onto other dielectrics (DoD deposition). NHC-based SMI can be effectively removed by either thermal annealing or plasma treatment. The use of NHCs as etching or atomic smoothing agents in semiconductor manufacturing is also being explored at the C2MCI.

Researchers at the C2MCI have also recently developed NHC-functionalized polymeric coatings. These coatings were successfully deposited on metal substrates (e.g., Au, Cu, Ti, Al, and steel) and metal powders (e.g. Cu, Ti and Al) using a variety of known techniques, including spray, electrodeposition, immersion, brushing, rolling, spinning, and vapor-phase deposition. The NHC-functionalized polymer coatings exhibited excellent durability, adhesion, and longevity, representing a new approach to protecting metals.

The strong metal–organic linkage has also been demonstrated in several sensing applications.

Further Details:

To learn more, visit the C2MCI website: .

Explore related C2MCI technologies here:

•  (Western University)
• Technology Overview:  (Western University)

Benefits

Coatings based on NHCs exhibit improved bonding with the metal substrate and, therefore, decrease the occurrence of failure by delamination. Additionally, in ‘bottom-up’ semiconductor manufacturing processes, NHCs offer a combination of thermal stability, selectivity, and structural tunability.

Applications

• Corrosion protection
• Semiconductor manufacturing
• Surface functionalization
• Sensors

Opportunity

C2MCI’s patent portfolio currently consists of four issued US patents, a total of seven patent applications pending in the US and Canada, three PCT applications, and six US provisional.

The C2MCI is seeking industrial partners interested in collaborating to develop NHC-based coatings in the areas of corrosion protection, semiconductor manufacturing, sensing and surface-functionalization.

IP Status

• Patent application submitted 
• Provisional patent 
• Patented

Seeking

Development partner

Posted/updated

June 3, 2025/June 18, 2025 (Technology Overview)