Tara Lyn Conley and Pratibha Mahale

Scientific advancement often begins with foundational questions, such as “Why?” or “How?” For example, Galileo’s astronomical investigations expanded our understanding of the universe, while Marie Curie’s research on radioactivity significantly contributed to both physics and medicine. Studies on DNA structure have furthered knowledge of biological processes. The scientific method encompasses exploring unknowns, formulating hypotheses, conducting experiments, and refining approaches based on outcomes. This process is often shaped by external factors, including regulatory requirements and consumer influence. Regulations can prompt scientists and innovators to reassess established methodologies, pursue alternative solutions, and explore emerging areas of knowledge. These compliance efforts have driven advancements in technologies such as architectural coatings and sustainable materials across various consumer markets.

Scientific curiosity-combined with evolving regulatory requirements and environmental concerns-drives innovation in architectural paints. The market, projected to reach USD 110 billion by 2032 (according to dataintelo.com), is fueled by urbanization, consumer interest in aesthetics, and growth in emerging regions. Key innovation drivers include increased awareness of indoor air quality, efforts to reduce environmental and health impacts, elimination of hazardous chemicals, and the pursuit of sustainability certifications. Stricter guidelines are pushing suppliers and manufacturers to adapt and collaborate, ensuring compliance while overcoming new challenges.

Modern paint makers are working to reduce or remove chemical groups such as per-and polyfluoroalkyl substances (PFAS), volatile organic compounds (VOCs), and biocides from their formulations.  Titanium dioxide (TiO₂) has faced scrutiny for its potential health inhalation concerns and environmental footprint, particularly due to energy-intensive mining that contributes to pollution and habitat loss. In 2020, European Chemicals Agency (ECHA) classified the powder form of TiO₂ as a suspected carcinogen by inhalation; however, the European Court of Justice recently annulled this classification¹. Regulatory bodies have set exposure limits for TiO₂. While it is safer in liquid paints, spraying or sanding can still release harmful particles, and skin or eye contact may cause irritation. Proper ventilation, respiratory protection, and thorough cleanup help minimize risks. Sustainability efforts now focus on both the climate impact and health concerns associated with TiO₂ ^2,3,4.

TiO₂ is prized in architectural coatings for its exceptional light-scattering ability properties, granting impressive opacity and coverage with fewer coats. In 2023, the global TiO₂ market reached approximately 6.6 million metric tons⁵, with the paint industry accounting for 55% of worldwide TiO₂ consumption⁶—a testament to its pivotal role in achieving high-performance finishes. TiO₂ bolsters UV resistance, color stability, durability, and overall weatherability, while also enabling smooth, glossy surfaces and, in some cases, self-cleaning properties through photocatalytic mechanisms⁷. Despite these advantages, TiO₂ has limitations. At high concentrations, or due to pigment flocculation, overlapping light-scattering domains can reduce its efficiency and ability to effectively mask surfaces.

Dow has pioneered advancements in hiding technologies since the 1950s, beginning with the introduction of TAMOL™ Dispersants to enhance pigment dispersion stability. Continued innovation throughout the 1980s and beyond led to the creation of ROPAQUE™ Opaque Polymer–a polymeric pigment capable of efficiently scattering light in a manner like TiO₂-enabling formulators to substitute up to 5% of TiO₂ without sacrificing hiding effectiveness. Dow’s latest development in TiO₂ technology emerged in the 2000s with EVOQUE™ Pre-Composite Polymer, which utilizes latex particle stabilization of titanium dioxide particles to optimize pigment spacing for maximum TiO₂ light scattering efficiency. This enables a reduction of TiO₂ content by up to 20%.  All of Dow’s hiding enhancement tools work seamlessly to deliver an optimized coating performance. For example, if a paint contains 2.5 lb/gallon of TiO₂, incorporating ROPAQUE™ Opaque Polymer andEVOQUE™ Pre-composite Polymer can reduce TiO₂ content by 15–25%, which equals a reduction of approximately 0.38–0.63 lb/gallon.

Figure 1: Illustrations showing the diminished hiding when TiO2 particles become overcrowded.

Dow’s ROPAQUE™ Opaque Polymer and EVOQUE™ Pre-Composite Polymer are technologies designed for pigment applications in architectural paints. Paints optimized with pigment spacing technology and the use synthetic hollow-sphere opacifiers, will enable effective hiding power with reduced TiO₂ content of up to 25% in a formulation. This adjustment maintains paint quality and reduces the environmental impact associated with TiO₂ production. For each share point of TiO₂ replaced globally, about 186,000 metric tons of CO₂ emissions can be lowered⁸.

Figure 2: Two hiding technologies that reduce the use level of titanium dioxide in paint.xxx

A cradle-to-grave life cycle analysis (LCA) demonstrated that using TiO₂-efficient binders and opacifying additives in flat to semigloss paints can reduce greenhouse gas emissions by up to 12%*, without compromising performance or significantly increasing other environmental impacts. The LCA measured the amount of paint needed for one square meter over a 60-year building lifespan. These innovations illustrate how regulatory, and sustainability goals drive technical improvements and help lower environmental impact.

Opaque Polymer Technology

TiO₂ positively influences paint quality but negatively impacts formulation cost and user health and safety due to potential inhalation concerns. In practice, increasing TiO₂ content yields diminishing returns; its contribution to opacity eventually reaches a limit. As illustrated in Figure 3, the film’s scattering coefficient plateaus with increasing TiO₂ levels because particle crowding leads to overlapping light-scattering spheres, reducing incremental light-scattering efficiency.  

Figure 3: Titanium dioxide light scattering efficiency decreases with increased use level.

Figure 4: A cartoon image of a ROPQUE(TM) Opaque Polymer particle with and without water, before and after drying. The difference in the refractive index between the styrene shell and air void provides efficient light scattering.

ROPAQUE™ Opaque Polymer is a synthetic hollow-sphere pigment that scatters light, allowing up to 5% replacement of TiO₂ in formulations. Composed of a styrene shell and a water-filled center, the polymer drains water as coatings dry, leaving a hollow core that reflects light efficiently without crowding (see Figure 4).

The styrene shell maintains air voids in the opaque polymer (OP), ensuring consistent opacity even at higher concentrations. This enables paint formulators to substitute TiO₂ with OP without loss of dried opacity. ROPAQUE™ Opaque Polymer is recommended when TiO₂ exceeds 1.5 pounds per gallon. Using OP instead of TiO₂ reduces particle crowding and preserves coating opacity, with a replacement guideline of 1:3% PVC for formulations containing more than 1.5 lb/gallon of TiO₂.

Dow continues to advance ROPAQUE™ Opaque Polymer chemistry. Figure 5 illustrates this progress, highlighting upcoming developments aimed at further reducing TiO₂ use and enhanced.

Figure 5: ROPAQUE™ Opaque Polymer evolution and the incremental S/mil increase with each iteration. The numbers above each bar in the graph is the year of development.

EVOQUE™ Pre-Composite Polymer

Dow’s EVOQUE™ Pre-Composite Polymer Technology improves the efficiency of TiO₂ in architectural coatings. As mentioned above, TiO₂ creates opacity through its high refractive index, but its cost, crowding, and environmental concerns require better efficiency.

Figure 6. SEM image of (a) regular paint (b) paint with EVOQUE™ Pre-Composite Polymer. Inset in (b) shows TEM image of a TiO2 composite with EVOQUETM Polymer. Corresponding schematic of TiO2 in (c) regular paint and (d) paint with EVOQUETM Pre-Composite Polymer.

EVOQUE™ Pre-Composite Polymer enhances TiO₂ performance by facilitating the formation of polymer-pigment composites that improve dispersion efficiency. In traditional formulations, TiO₂ particles often agglomerate, resulting in overlapping scattering domains and reduced optical effectiveness. EVOQUE™ Polymers associate with the TiO₂ surface to form a structured composite, optimizing inter-particle spacing, reducing crowding, and ensuring uniform distribution across the film matrix. Figure 6 shows the enhanced TiO₂ distribution within paint film with EVOQUE™ Pre-Composite Polymer compared to conventional paint, as observed via SEM.

This spatial refinement increases the effective scattering cross-section of individual TiO₂ particles, significantly improving light-scattering efficiency. As a result, formulators can achieve superior hiding power at equivalent TiO₂ loadings or reduce TiO₂ content by up to 20% without compromising opacity or overall film integrity. Figure 7 presents the elevated scattering coefficient per unit thickness for an EVOQUE™ Binder compared to a standard acrylic binder.

Figure 7. Scattering coefficient per mil as a function of TiO2 PVC for a standard acrylic binder and EVOQUE™ Binder.

EVOQUE™ Binder enhances both interior and exterior paints by improving pigment distribution, which strengthens film structure and boosts stain resistance, cleanability, tannin blocking, corrosion resistance, and durability (Figure 8 and 9). Successive EVOQUE™ generations of binders have continually improved these attributes across various coatings.

Figure 8. Overview schematic of EVOQUE™ Pre-Composite Polymer Technology and film structure.

Figure 9. (a) Household stain removal of conventional vs composite interior paints and (b) Exterior durability of conventional vs composite paints.

The architectural paint industry is at a pivotal moment where sustainability and innovation must go hand in hand. Innovations such as ROPAQUE™ Opaque Polymer and EVOQUE™ Pre-Composite Polymer have revolutionized TiO₂ optimization, offering significant environmental benefits without compromising performance. A cradle-to-grave life cycle assessment (LCA) study found that in high-quality flat to semigloss paints, TiO₂-efficient binders combined with opacifying polymeric additives can reduce greenhouse gas emissions by up to 12%*, without sacrificing performance or significantly increasing other environmental impact categories. This finding underscores the potential for innovative materials to drive the industry towards a more sustainable future-balancing environmental responsibility with the high standards of quality and durability that consumers expect. As we move forward, continued research and collaboration will be essential in achieving these goals and ensuring a greener, more sustainable world.

* This information is formulation dependent and came from a Dow internal lifecycle assessment and has not been critically reviewed externally and as such is subject to revisions.

1.ECHA website:  https://echa.europa.eu/-/new-guide-available-on-classifying-and-labelling-titanium-dioxide

2. Savastano, D. (2025). EU’s Titanium Dioxide Ruling Sparks Concern. Coatings World. Retrieved September 9, 2025, from https://ajay.cw.rodmanadmin.com

3. National Institute for Occupational Safety and Health (NIOSH). (2011). Current Intelligence Bulletin 63: Occupational Exposure to Titanium Dioxide (DHHS Publication No. 2011-160). Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/niosh/docs/2011-160/

4. Canadian Centre for Occupational Health and Safety (CCOHS). (2025, August 28). Titanium dioxide – OSH answers fact sheet. https://www.ccohs.ca/oshanswers/chemicals/chem_profiles/titanium_dioxide.html

5. Market Growth Reports. (2025, August 25). Titanium Dioxide (TiO₂) Market Size, Share, Growth, and Industry Analysis. Retrieved September 14, 2025, from https://www.marketgrowthreports.com

6. Adams, R. (2020, January 8). Titanium dioxide: “World demand shows a pattern that is far from smooth”. European Coatings. Vincentz Network. Retrieved September 14, 2025, from https://www.european-coatings.com

7. Mohamadpour, F., & Amani, A. M. (2024). Insights into TiO₂-based photocatalytic systems. Catalysts, 9(8), 680. https://www.mdpi.com/2073-4344/9/8/680

8. Based on Dow estimates for PCF for titanium dioxide from TDMA.