Research Overview

 

 

Coatings' Material Science

Coating deterioration in weathering

• Modelling: statistical approaches, Monte Carlo simulations, finite element analysis
• Changes in physical properties of coatings, and their interconnections
• Corrosion protection, adhesion etc.
• Water and electrolyte uptake

Film Formation

• Molecular dynamics of crosslinked polymers: network formation and properties
• Drying behavior

Internal Stresses in Films

• Effect on adhesive and cohesive properties
• Effect of mechanical stresses during weathering

Art Conservation

• Application of coatings' and materials science to the preservation and restoration of painted art

History of Paint Technology

• How external events, polymer science, pigment development and analytical instrumentation lead to the development of paint technology . Please send me a message if there is an error in my attempt at paint history, or there is additional information that I can add.

A bit more:

Weathering Durability

The studies of weathering durability are focused on polymeric coatings, but there is no reason why the modeling approaches should not apply to any material that suffers an aggressive environment.

The modeling uses the recognition that a huge number of aggressive molecules, photons and other events arrive at random times and random places across an exposed material. This means that Monte Carlo simulations of these processes, or the use of the statistics of random processes, via the Central Limit Theorem, can be used to gauge how damage accumulates at the surface (they get rougher, and change chemically) or within the bulk of a material. The extent of damage can be linked to physical properties via some very well known (and venerable) ideas, e.g. the Griffith fracture criterion. In principle, the Monte Carlo approach can be as exact as our knowledge of the composition of our material and its degradation mechanisms. Unfortunately, even modern computers struggle to produce results within reasonable periods so we have tended to derive simple algebraic models assuming weathering is a stochastic process. In these models, we have no ambitions about capturing all the details, but we hope to provide some simple, but useful, guidance based on physics and chemistry (no arbitrary curve fitting) for those who want to understand the parameters that determine deterioration and how to compare their candidate materials. In this work, we have derived simple relations for how gloss loss, contact angle, fracture strength, yellowing and corrosion protection diminish with exposure that assume that accumulated damage determines the failure.  Depending on the property of interest, degradation depends on either the average amount of damage or the greatest amount of damage (which can be accessed using extreme value statistics). 

Experimental work has focused on how appearance properties, surface topography and water uptake change during weathering and link them to corrosion protection (usually electrochemical impedance spectroscopy) and other aspects of physical durability.

 

History of Paint Technology

Occasionally, I get involved with art historians and conservators, primarily when the field wants someone to discuss old paint technology.  I was not actually around when the old masters and even modern artists used paints, but I can understand the materials that they used and I can explain how material variation occurred and the consequences. It has been fascinating to learn how artists view their media and to see how subtleties in material composition determine how paint performs and changes over much longer periods than the average DIYer or contractor would worry about. Apart from my background, my advantage is that there has been paint research at NDSU since 1905, so the library has an enviable archive of old books and journals to peruse when people call for help.  For its own sake, although it may not be a glamorous topic, it is interesting how external events (wars, shortages), polymer science, pigment development and analytical instrumentation all lead to the current state of paint technology.  It is a humbling experience for a scientist to discover how much art historians know.