New Corrosion Protection Material Repairs Itself


Researchers at ETH Zurich have reportedly developed a plastic corrosion protection material that glows in places where it is not damaged, repairs itself and can be reused multiple times.

The work on this novel material, lead by Markus Niederberger and Walter Caseri from the Laboratory for Multifunctional Materials, was published in the journal Polymers. ETH researchers also collaborated with partner universities in Spain, Austria, Italy and the United Kingdom.

About the Material

The development of the material reportedly came out of “pure chance,” as researchers were working on the product of nanoparticles in a special organic solvent. However, under certain conditions, the solvent would become solid and polymerized.

“That was unintentional and unwanted,” Niederberger recalled. “We didn’t know what to do with it at first either.”

Despite being created by accident, researchers began refining the material into poly(phenylene methylene), or PPM, and also discovered that it had a high thermal stability and fluoresced.

Laboratory tests then revealed that a PPM-based coating could protect metals such as aluminum against corrosion. Researchers report that the protective coating can be applied in layers that are up to 10 times thinner than conventional protective agents, and it is durable.

Additionally, the polymer can seal any damage to the coating itself without any additives, the researchers say.

According to the university’s release, countries globally invest about 3.5% of annual gross domestic product in corrosion protection, amounting to more than $4,000 billion.

Once mixed as paint and heated, PPM can be sprayed onto a surface and become a solid. Then, the polymer can indicate holes and cracks in the protective layer by failing to fluoresce.

It is reportedly more sustainable than other corrosion protection materials, due to its ability to be completely removed and recycled at the end of the product’s life. Some polymer material is lost in this process, but remains at a recycling rate of 95%.

Researchers found that they could reuse the material five times in testing. This material also reportedly performs better than epoxy-based corrosion protection materials in regards to environmental impact and human health.

“There are really only two disposal solutions for epoxy resins: incineration or landfill,” said doctoral student Marco D’Elia. “Our product allows for a third solution: recycling.”

D’Elia hopes to see the product commercialized, with the team looking for an industry partner to further develop the product, as well as manufacture and distribute it on a large scale. The researchers have applied for a patent for the invention.

“Our technology is pretty advanced, but before we can sell it as a product, there are still some improvements for us to make,” D’Elia said.

Corrosion Forecasting

Last year, a group of researchers called for a “paradigm change” in the science of forecasting corrosion damaged within reinforced concrete structures. The commonly used theoretical concept to predict corrosion in these scenarios—a chloride threshold—was critically reviewed by the team and reportedly presents a major barrier for developing reliable forecast models.

According to the researchers, the most common cause of degradation and failures of reinforced concrete structures is chloride-induced corrosion of its embedded steel. A widely-used concept called the chloride threshold is used as a model to forecast corrosion performance of reinforced concrete structures exposed to chloride environments.

The team, made up of scientists from Switzerland, the United States, Canada and Norway, reported that, prior to the COVID-19 pandemic, they met to discuss the flaws in using the chloride threshold concept for forecasting corrosion.

When concrete is exposed to salts, like seawater or road salts, those chloride ions can penetrate the concrete due to its porous nature and reach the steel. Eventually, the protective passive layer is destroyed and causes corrosion.

However, the rate of corrosion depends on the exposure conditions. Steel corrosion in concrete is a continuous process and not often separable into uncoupled, sequential phases.

According to the release, because of this, the researchers said the focus should be placed on the quantification of the time- and space-variant corrosion rate from the moment steel is placed within concrete until it reaches the end of its service life.

Ueli M. Angst from ETH Zurich and the research team proposed that scientific research evolve away from the chloride threshold concept. Instead, “a multiscale, multidisciplinary approach combining scientific and practical contributions from materials science, corrosion science, cement/concrete research and structural engineering” is needed, according to the study.


Tagged categories: Asia Pacific; Coating Materials; Coating Materials; Coatings; Colleges and Universities; Corrosion; Corrosion protection; EMEA (Europe, Middle East and Africa); Green coatings; Latin America; North America; Program/Project Management; Protective Coatings; Protective coatings; Research and development; Self-healing; Sustainability; Z-Continents

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