Advanced Coatings Science & Innovation Seminars

Automotive clearcoats are expected to deliver long-lasting gloss and protection, even under frequent mechanical stress from washing and everyday use. Traditional approaches to improving scratch resistance rely on making the coating harder through increased crosslinking, but this strategy reaches natural limits of carbon-carbon bond and can make the coating brittle. Hard particles such as silica are another option, yet they typically distribute evenly throughout the film, which means a high amount is needed before the surface performance improves.

We introduce a new approach that allows silica to move preferentially toward the surface during film formation. By pairing the particles with a specially designed carrier resin, the additive becomes surface-active, enabling stronger scratch and mar resistance at lower loadings and cost-effective option. This translates directly into better durability during car washes, improved resistance to everyday rubbing or contact, and enhanced protection against dirt accumulation and graffiti.

Because the carrier-resin concept can be applied to other functional materials, it opens new opportunities for developing clearcoats with targeted and more efficient surface performance.

Roughness and chemistry dictate whether a surface behaves in an adhesive or an abhesive manner. This is critical if the objective is to generate an adhesive bond or a coating to adhere to a part or whether the aim is to have a surface to which contamination does not adhere. The interdependence of roughness and chemistry on these behaviours is subtle and whilst broad guidelines may well be sufficient in many cases, a deeper understanding can reveal the potential for limitations and opportunities to improve reproducibility and functional behaviour. The presentation will provide background to the assessment of roughness and wetting behaviour and how these behaviours influence each other, I will also discusses the need for integrated, multiscale characterisation and design strategies combining chemistry, topography, and mechanics to achieve predictable interfacial performance.

This research describes a versatile method for the creation of multi-tier hierarchical structured surfaces, that seek to optimise conflicting surface effects, such as anti-viral/anti-microbial efficacy and hydrophobic (easy-clean) properties. This approach exploits the availability of surface-active ‘chemical functional’ groups whilst also manipulating surface micro- and nano-structure, to control the way the coating interacts with liquid droplets. Further to this, the methodology highlights a new and valuable route to mechanically robust, nano-structured surfaces which outperform control coatings over multiple abrasion cycles. The approach utilizes a simple spray application process to create the robust structured surfaces, doing so without the use of specialist equipment. Finally, this approach is presented as a potential route to ‘self-decontaminating surfaces’ that can capture and remove hazardous chemicals from surfaces.

The use of silane modified colloidal silica in PUD resin-based coating formulations in combination with resin and epoxy silane has been investigated. The samples were evaluated regarding their mechanical, physical properties and corrosion resistances on galvanized steel.

Addition of modified colloidal silica enhanced the corrosion resistance significantly. The coating cross-linking density increased upon silica and silane addition. Synergy between silane, colloidal silica and resin in corrosion resistance could be noted but did not correlate to any further increase in cross-linking density.

A good compatibility was observed, hardness of the coatings were in agreement with their good flexibility and impact resistance.