Lignin-based SLIP offers a route beyond PFAS waterproofing

By Olivia Hart

Replacing polyfluoroalkyl substances (PFAS) in waterproofing with a lignin-based material could avoid $1.1 billion in annual societal damage, according to a Texas A&M University estimate of global human-health and environmental effects from forever chemicals.

Washington University in St. Louis researchers published the work in Matter and named their material SLIP, short for superhydrophobic lignin-integrated particles. The estimate describes potential avoided social costs, not a forecast of coating sales or producer revenue.

What is SLIP made from?

PFAS underpin safe packaging, fire protection and waterproof coatings, yet they impose a multibillion-dollar burden on human health and the environment. PFAS materials remain relatively affordable and abundant. WashU chemical engineers sought another feedstock with similar practical merits and chose lignin, a plant-waste material.

Joshua Yuan and his team, including first authors Puneet Dhatt and Weiwei Li, used plant vascular tissue as their model. Xylem carries water through plants; suberin, a waterproof molecule within it, provided the structural cue. The researchers linked lignin particles to fatty acids and added a polylactic acid binder.

The resulting material combined high superhydrophobicity with mechanical robustness and ultraviolet stability. Yuan, the Lucy & Stanley Lopata Professor and chair of energy, environmental and chemical engineering at WashU McKelvey Engineering, also directs the NSF Carbon Utilization Redesign for Biomanufacturing Energy Research Center. His wider work uses natural systems as models for replacing petrochemical-based materials.

The takeaway is straightforward: SLIP starts with waste lignin and three main inputs designed for industrial coatings.

What can the coating do?

Tests showed water bouncing off the SLIP surface. “The water will just run off,” Puneet Dhatt said. Researchers also tested the coating against wood-degrading fungus and found that it could break down into harmless organic matter within the expected period.

Yuan said SLIP can degrade rather than remain in the environment indefinitely. Dhatt noted that lignin and fatty acids evolved to break down in the environment over long periods. Together, the researchers said, that behavior could avoid some societal costs associated with forever chemicals.

The team does not claim that SLIP matches every function of PFAS. It describes the material as a substantial start, particularly because modern manufacturing uses a large number of waterproof coatings.

The takeaway: SLIP has shown water repellency and degradation under laboratory testing, but it is not yet a full PFAS replacement.

What does the $1.1 billion estimate show?

Texas A&M researchers collaborated with the WashU team to assess the global human-health and environmental effects of replacing forever chemicals with SLIP in waterproofing. Their calculation puts potential annual societal damage avoided at $1.1 billion.

That figure represents avoided social cost, not SLIP revenue, annual tonnage coated or producer profit. The announcement gives no production capacity, commodity price per tonne, customer commitment or regulatory timetable. Without a disclosed volume and rate of substitution, the estimate does not become a market forecast.

Yuan described the study as a model for learning from nature and designing a sustainable material critical to society, with a life cycle similar to natural polymers. He said: “...where everything can degrade without causing harms.”

His statement sets a high bar: a coating must match industrial performance while avoiding the persistence that drives PFAS costs. So far, the research demonstrates one important function, water resistance, plus early degradation evidence.

The $1.1 billion case is an avoided-damage estimate, not evidence of commercial demand.

What has to happen before market use?

Researchers say SLIP could be used in packaging and construction-material coatings. The next technical targets are to make it oil- and fireproof, which researchers say would expand its applications. The team is also working to scale up the process and integrate it with biorefinery and paper and pulping industries.

None of that work amounts to an operating commercial plant. The announcement gives no installed annual capacity, launch date, customer pilot, permit approval or regulatory filing. SLIP remains a research-stage material moving toward scale-up, not a coating product already replacing PFAS on the market.

The market milestone is a scaled process that adds oil- and fireproof performance and can supply packaging or construction coating markets. Until then, the $1.1 billion figure remains an avoided-cost scenario rather than a sales forecast. The chemistry has a plan; the factory does not.