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Surveying The Scene

  • ACC survey identifies Water-borne, VOC, and customer demands as very important

  • Scientists create coating with hydrophilic & oleophobic properties for oil & gas industry

  • US Patents for eco-friendly & biocompatible coatings

  • Rapid, non-invasive characterization of the dispersity of emulsions via microwaves

ACC survey identifies Water-borne, VOC, and customer demands as very important

A RECENT survey done during the American Coatings Conference organisers has thrown up many interesting results. The significance of water-borne systems was highlighted with more than 50 percent of votes going in for these systems indicating that it was the most important future technology in their industry sector. Nearly a quarter of those polled chose smart or functional coatings as eminent for their operations. High-solids (13 percent) and UV/EB (6 percent) ranked third and fourth, respectively. Five percent saw powder coatings as the most important technology.

When asked about the drivers for R&D activities, the audience identified customer demands (56 percent) as most important. The results for the other options were very close: cost reduction and sustainability both held a share of 13 percent of the votes. Legislation & regulation followed closely with 11 percent.

Raw material availability was not such a strong driver, as only seven percent choose this factor. Customer demands also ranked first as the hottest topic on the current companies' agenda. More than a third voted for this option. The second most votes gained the answer “identifying new markets.” This comes as no surprise, as in one of the earlier asked questions some 70 percent voted North America as their most important market. Raw material prices and availability was a hot topic with 24 percent.

VOC was clearly the top-seed for the most important regulatory issue. More than 60 percent in the audience gave their vote to this answer. Labeling and hazard communications ranked second with 21 percent. Food contact (14 percent) and indoor air quality (five percent) were of lower importance, according to the polling results.

Scientists create coating with hydrophilic & oleophobic properties for oil & gas industry

SCIENTISTS at the U.S. Department of Energy's (DOE) Argonne National Laboratory have developed a novel approach, which addresses the problem of Crude oil cloging filters membranes and other equipment used in the oil and gas industry and will prolong the lifetime of key industrial equipment.

The new invention consists of a type of coating that produces thin films of water-loving, oil-repelling molecules on the surface of filter membranes. These metal oxide molecules grab onto any loose water atoms while resisting oil. To scientists, these twin properties are known as hydrophilicity and oleophobicity.

“One of the best ways to clean oily water is with membranes,” said Seth Darling, Director of the Institute for Molecular Engineering at Argonne. “The problem is that the oil sticks on the membrane and clogs the holes until the membrane stops working. Today, if people have an oil-fouled membrane, either they replace it or they try to clean it with harsh chemicals to wash away the oil.”

The scientists used a method called atomic layer deposition, which uses chemical vapors to deposit a very thin coating of the metal oxide on all of the filter membrane surfaces. They experimented using different metal oxides on off-the-shelf commercial polymer membranes to find which ones worked the best. The team published the results in ACS Nano on August 14.

Atomic layer deposition itself isn't new, but it's never been used this way to modify membranes before, Darling said.

Coating with Minimum Thickness

“It's kind of cutting edge,” Darling said. “The coating is just a few nanometers in thickness. If the coating were thicker than this, it would close off the tiny pores. What you want is a minimal change of the pore structure, but you want to change the chemistry of the substance lining those pores.”

To create this layer in the past, people tried to attach nanoparticles to a membrane by flowing them through it or growing them on it. But particles tend to get ripped off as water flows through those systems. Atomic layer deposition is different because the metal oxide film, in this case, forms strong chemical bonds with the polymer to which it is adhered. In the atomic layer deposition process, the membrane is exposed to a sequence of vapors that stick molecules together, forming covalent bonds with the polymer.

“Some polymers bind more easily than others, and some repel oil while others do not,” Darling said of his group's process working with a variety of metal oxides. “At this point, we have a pretty good sense of which ones work and why.” Tin oxide and titanium oxide formed the tightest bonds with water molecules, capturing them and layering them across the surface.

“When oil contacts the membrane, it will stay separate because it flows over the water layer,” said Hao-Cheng Yang, a postdoctoral researcher working on the project.

Fouled membranes can be a costly hassle for the oil and gas industry. For instance, when oil companies replace clogged filters during the hydraulic fracturing process, they have to shut down their equipment to make the change. Oil-resistant membranes like this could significantly reduce the need for both filter replacement and the downtime it creates, said John Harvey, Argonne's business development executive handling the technology.

“Just from my knowledge of the oil and gas sector, if we could make a membrane that performs to even a fraction of what we've seen in lab testing, it will be a phenomenal improvement over what's available now. That represents a huge savings,” said Harvey.

Another problem in the industry involves the water used in fracking, which often returns from the ground with oil, salt and other contaminants present. Contaminated water cannot be returned to the ground if it poses a threat to aquifers, so the industry often must find another way to dispose of it.

The membranes used now can remove the other contaminants, but they become fouled by oil. The atomic layer deposition process keeps the membranes from clogging to better filter the water passing through them.

“With this technique, they can keep using that water,” Harvey said. “This could be a direct replacement for filter units they're using today.”

The method could also help in oil spill cleanup efforts. In an oil spill response, diesel fuel is used as a cleaning agent on pipes and containers, which leaves a waste of diesel mixed with oil and dirt. But pipe and container surfaces treated with the oxides could just be rinsed clean, noted Darling.

Darling, who also invented the Oleo Sponge, a material that can soak oil out of sea water, said he thinks the two technologies could be used in concert for future cleanups — and also for a host of things that he and his fellow scientists probably have not thought of yet.

“One thing I learned from the Oleo Sponge is that you can't envision all the possible applications at the beginning,” he said. “We anticipated interest from oil companies, but we've also heard from the cosmetics industry and from sporting goods manufacturers. So I suspect once this gets out, people will also come up with applications we never imagined.”

The scientific team also included Argonne's Jeffrey Elam and Lin Chen, who work in the Applied Materials division, and Ruben Waldman from the University of Chicago. Much of the work was performed at the Center for Nanoscale Materials, a DOE Office of Science User Facility, located at Argonne.

The article is titled “Crude-Oil-Repellent Membranes by Atomic Layer Deposition: Oxide Interface Engineering.” The research was funded through Argonne's Laboratory Directed Research and Development Program.

US Patents for eco-friendly & biocompatible coatings

KETTERING University has announced that its Chemistry and Chemical Engineering faculty and former students have been granted two patents in 2018. Chemical Engineering faculty members Dr. Mary Gilliam and Dr. Susan Farhat, Chemistry faculty member Ali Zand, and former students collaborated on the work that lead to the patents.

One patent is on a method for chemically changing the surface of micro and nanoparticles to expand the use in applications such as composites, paints and coatings, and biomedical applications.

The other is on coatings for internal biomedical devices, such as hip and knee implants, to increase the lifetime and potentially reduce the chance of inflammation or rejection.

Patent #1: Surface Treatment of Particles to Increase Affinity for Water

The first patent, “Gilliam, M., Farhat, S., Garner, G., Magyar, M. Method and Apparatus for Surface Chemical Functionalization of Powders and Nanoparticles. U.S. Patent No. 9,994,683 June 12, 2018”, is for a method of treating the surface of nano and microparticles with atmospheric plasma to chemically modify the surface of the particles.

One example of the invention was published in the peer-reviewed journal Plasma Processes and Polymers in 2014, in which hydrophobic polymer particles were treated using the plasma process, which resulted in a greater affinity for water. “The article highlights the versatility of the atmospheric pressure process that can enable a wide variety of chemical changes through numerous types of chemicals that can be injected into the plasma or added directly to the stream of plasma-treated particles,” Gilliam said.

The process also offers an alternative surface treatment method that has a low environmental impact and can be scaled up to larger manufacturing processes. “In one aspect, the treated particles could disperse into water without another solvent or added surfactant,” Farhat said. “Water is very safe, and it's environmentally friendly. The process can be performed continuously using plasma at atmospheric pressure so it could be easily commercialized.”

Graham Garner '18 and Michael Magyar '16, both of whom majored in Chemical Engineering, played key roles as undergraduate students in developing the process and conducting the experiments. “It was something I was not expecting right away when I started at Kettering,” Garner said. “You think it's something you'll do later. It's kind of overwhelming in a way.”

Patent #2: Water-resistant & Biocompatible Medical Coatings

Gilliam, Farhat, and Zand were granted another patent, “Gilliam, M., Farhat, S., Zand, A. Wear Resistant and Biocompatible Coatings for Medical Devices and Method of Fabrication. U.S. Patent No. 10,058,889”, in August for a surface treatment for biomedical devices.

In a hip replacement, a metal ball and joint with a plastic insert will replace the hip socket. As the ball moves, the materials start to wear and the body's cells may start attacking the particles and eat away at the bone. They incorporated the atmospheric pressure plasma treatment to graft a non-toxic, biocompatible coating on the plastic surface that reduces friction and wear. The coatings on the plastic surface significantly decreased the surface wear, which was attributed to the chemical changes and increased hydrophilicity. Cell viability tests using Mouse Embryonic Fibroblast cells showed that the coatings and surface treatments were non-toxic. Future work with the coatings process can include embedding drugs into the coating to fight infection, which can be a problem with joint replacements.

The coatings have been demonstrated in two published, peer-reviewed articles in Surface and Coatings Technology and the Journal of Biomaterials Science: Polymer Edition. The work involved several undergraduates students and a cross-disciplinary team at Kettering from Chemical Engineering, Chemistry, and Biology, and McLaren Regional Medical Center. The coatings on the plastic surface significantly decreased the surface wear, which was attributed to the chemical changes and increased hydrophilicity. Cell viability tests using Mouse Embryonic Fibroblast cells showed that the coatings and surface treatments were non-toxic. Future work with the coatings process can include embedding drugs into the coating to fight infection, which can be a problem with joint replacements.

Rapid, non-invasive characterization of the dispersity of emulsions via microwaves

A RAPID and non-invasive method to determine the dispersity of emulsions has been developed based on the interrelationship between the droplet size distribution and the dielectric properties of emulsions. A range of water-in-oil emulsions with different water contents and droplet size distributions were analysed using a microwave cavity perturbation technique together with dynamic light scattering. The results demonstrate that the dielectric properties, as measured by non-invasive microwave cavity analysis, can be used to characterise the dispersity of emulsions, and is also capable of characterizing heavy oil emulsions. This technique has great potential for industrial applications to examine the sedimentation, creaming and hence the stability of emulsions. This study was published in: Chemical Science Issue 34, 2018 by Yuqiang Yan, Sergio Gonzalez-Cortes, Benzhen Yao, Daniel R. Slocombe, Adrian Porch, Fahai Cao, Tiancun Xiao and Peter P. Edwards from the School of Chemical Engineering, East China University of Science and Technology; Department of Chemistry University of Oxford and the School of Engineering, Cardiff University n

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