Waterborne coatings significantly reduce VOC emissions and improve air quality compared to traditional solvent-based systems. They offer strong performance, durability, and versatility across architectural, industrial, and automotive applications. CoatingsTech talks with Dr. James W. Rawlins from the University of Southern Mississippi about the future of waterborne coatings both in the industry and at the university level.
Q: What are the most recent noteworthy advancements in waterborne performance?
A: In the last few years, exterior-durable latex platforms enabled by reactive polymer-bound surfactants have been a consequential step forward. By copolymerizing reactive/polymerizable surfactants into the latex backbone, concerns associated with surfactant migration, water uptake, and sensitivity have been mitigated, which have historically been issues with waterborne films. Additionally, modern waterborne polyurethanes and polyurethane/acrylic hybrids are now becoming available from experimental/laboratory and commercial materials.
Q: Where is the next big leap likely to come from?
A: There is a lot of research activity happening right now. Innovations in dynamic covalent networks show near-urethane mechanical energy absorption methods, resulting in circularity, repairability, and potential recyclability, in addition to higher crosslink network control and tunable mechanical deformation processes. There is also significant work being done on designed stratification and hybrid lattices in PU-acrylic and silicone-acrylic systems.
In the short term, there is strong progress coming from advancements in additives. Reactive and anchored additives are particularly promising. Another strong area in additives is platelet barriers and rare-earth/organophosphate inhibitors, but the fastest acceleration is happening in testing and digital technology. New methods are being developed for early detection and quantification of failure before they become visible macroscopically.
Q: How can formulators meet sustainability targets without sacrificing durability?
A: In several ways. Water uptake could be reduced at the source by using reactive surfactants and polymer-bound stabilizers, and free, mobile surfactants could be avoided wherever possible. Crosslink density should be driven down with low volatile organic compound chemistry: driven mainly through carbodiimide, blocked-isocyanate, or self-crosslinking mechanisms in acrylic/polyurethane dispersion hybrids. Barriers could be built but understanding and quantifying water, electrolyte, and oxygen barrier differences for common chemistries is needed.
Q: How do university–industry collaborations accelerate innovation?
A: Learning is best achieved through immersion. The combination of total immersion and timeline-driven projects, which is something industry needs, with solid fundamentals such as scientific goals and objectives in an integrated team, drive real depth and real-knowledge gains through necessity. These combined teams are driven by student enthusiasm, industry support, and passionate scientist and engineering personnel with experience. Flagship consortia move students from working with the theoretical to the practical, with fundamental concepts moving into products, as well trained and developed students drive new paradigms.
Q: What excites you most about the future of waterborne coatings?
A: There are many. One is one-pass which are self-organizing films, stratifying hybrids, that can deliver stain resistance and direct-to-metal (DTM) corrosion without extra layers. Another important contribution is novel material compositions that are sustainable and circular, and dynamic networks enabling repairable, recyclable waterborne films with high chemical resistance. Lastly, data-driven developments such as AI data gathering for machine learning that is linked to accelerated tests in a context of real test results are beginning to remove blind spots for unquantified or poorly connected concepts and this improves upon our scientific rationale moving forward and shrinks lab-to-field translation cost and time.
James W. Rawlins is a professor of Polymer Science and Engineering at the University of Southern Mississippi, where he has directed an 11-member research group focused on Surface Coatings and Circular Materials since 2004. Rawlins, chairman of The Waterborne Symposium, has published 61 peer-reviewed articles and holds 17 U.S. and European patents. Earlier, he served as technical director at Highland International and held R&D and European technical marketing roles at Bayer (now Covestro) in Pittsburgh and Leverkusen.