“Self-Healing” epoxy resins brings perovskite solar closer to market
A protective layer of epoxy resin helps prevent the leakage of pollutants from perovskite solar cells (PSCs), report scientists from the Okinawa Institute of Science and Technology Graduate University (OIST). Adding a “self-healing” polymer to the top of a PSC can radically reduce how much lead it discharges into the environment. This gives a strong boost to prospects for commercializing the technology.
With atmospheric carbon dioxide levels reaching their highest recorded levels in history, and extreme weather events continuing to rise in number, the world is moving away from legacy energy systems relying on fossil fuels towards renewables such as solar. Perovskite solar technology is promising, but one key challenge to commercialization is that it may release pollutants such as lead into the environment — especially under extreme weather conditions.
“Although PSCs are efficient at converting sunlight into electricity at an affordable cost, the fact that they contain lead raises considerable environmental concern,” explains Professor Yabing Qi, head of the Energy Materials and Surface Sciences Unit, who led the study, published in Nature Energy.
“While so-called 'lead-free' technology is worth exploring, it has not yet achieved efficiency and stability comparable to lead-based approaches. Finding ways of using lead in PSCs while keeping it from leaking into the environment, therefore, is a crucial step for commercialization.”
This perovskite solar module is better able to contain the lead within its structure when a layer of epoxy resin is added to its surface. This approach to tackling a long-standing environmental concern helps bring the technology closer to commercialization.
Testing to destruction
Qi's team, supported by the OIST Technology Development and Innovation Center's Proof-of-Concept Program, first explored encapsulation methods for adding protective layers to PSCs to understand which materials might best prevent the leakage of lead. They exposed cells encapsulated with different materials to many conditions designed to simulate the sorts of weather to which the cells would be exposed in reality.
They wanted to test the solar cells in a worst-case weather scenario, to understand the maximum lead leakage that could occur. First, they smashed the solar cells using a large ball, mimicking extreme hail that could break down their structure and allow lead to be leaked. Next, they doused the cells with acidic water, to simulate the rainwater that would transport leaked lead into the environment.
Using mass spectroscopy, the team analyzed the acidic rain to determine how much lead leaked from the cells. They found that an epoxy resin layer provided minimal lead leakage — orders of magnitude lower than the other materials.
Researchers exposed the solar cells to brutal conditions to simulate worst-case weather scenarios. Adding a self-healing epoxy resin polymer to the cell minimized the leakage of lead from the cell.
Enabling commercial viability
Epoxy resin also performed best under a number of weather conditions in which sunlight, rainwater and temperature were altered to simulate the environments in which PSCs must operate. In all scenarios, including extreme rain, epoxy resin outperformed rival encapsulation materials. Epoxy resin worked so well due to its “self-healing” properties. After its structure is damaged by hail, for example, the polymer partially reforms its original shape when heated by sunlight. This limits the amount of lead that leaks from inside the cell. This self-healing property could make epoxy resin the encapsulation layer of choice for future photovoltaic products.
“Epoxy resin is certainly a strong candidate, yet other self-healing polymers may be even better,” explains Qi. “At this stage, we are pleased to be promoting photovoltaic industry standards, and bringing the safety of this technology into the discussion. Next, we can build on these data to confirm which is truly the best polymer.”
Beyond lead leakage, another challenge will be to scale up perovskite solar cells into perovskite solar panels. While cells are just a few centimeters long, panels can span a few meters, and will be more relevant to potential consumers. The team will also direct their attention to the long-standing challenge of renewable energy storage.
Left to right. Group Leader Dr. Luis Ono, First Author Dr. Longbin Qiu, and Unit Head Prof. Yabing Qi, all of the Energy Materials and Surface Sciences Unit.
Nanocoating prevents greasy smears
NOT only are greasy fingerprints on shiny stainless steel surfaces unattractive, they also attack the surface in question. A new nanocoating being developed by Fraunhofer researchers will in the future prevent the annoying smudges that result from fingers touching stainless steel surfaces. The key to their approach: special nanoparticles added to the coating.
The shiny new refrigerator features an attractive stainless steel front. But it doesn't take long before the door is covered in dark fingerprints that are difficult to remove with only a cloth and detergent; the job actually calls for some arduous polishing. Fingerprints like these are more than just unsightly, the grease film also attacks the metal surface.
Say goodbye to greasy smears
Together with their colleagues at FEW Chemicals GmbH in Wolfen, researchers from the Fraunhofer Institute for Microstructure of Materials and Systems IMWS in Halle are now working to put an end to smears like these. The secret lies in a coating layer containing special additives and which is water and oil repellent. This layer's effects are twofold: When the particles integrated in the coating settle on the surface of the stainless steel, the surface becomes rougher and its surface area increases. When a finger comes into contact with the refrigerator door, it only touches the raised points on the surface and the grease on the fingertip never reaches the “valleys” of the stainless steel surface. This means the surface area which actually comes into contact with the grease is kept very small. In addition the refractive index of the coating has been adjusted so that it matches that of the skin's natural oil content. This means light is reflected by the coated stainless steel surface in about the same manner as by a surface that has been touched by sticky fingers. As a result, the fingerprints are hardly noticeable.
Analysis of the layer systems
While FEW Chemicals GmbH is handling the development of the coating systems, the Fraunhofer team is concentrating on the analysis of these layers. “We're investigating the layers created using not only optical microscopy, but also scanning electron microscopy and atomic force microscopy. We look at how large the individual particles in the coating system are and whether or not they are distributed homogenously. The effect of the additives used is another focus of our analysis,” says Dr. Jessica Klehm, research associate in the business unit “Biological and Macromolecular Materials” at Fraunhofer IMWS. Such questions are extremely important in the assessment of the quality of the coating. For example, if the nanoparticles aggregate to form larger particles, the coating may lose its transparency as a result. On the other hand if the particles are too small, the surface remains too smooth, so that the grease film can adhere to it over larger areas in spite of the coating.
Several challenges had to be overcome before these investigations could be conducted. First and foremost, the samples had to be recuced in size. Optimum investigations with optical microscopy as well as further investigation with other methods requires the samples to have a thickness of no more than 60 to 80 micrometers, i.e. about the thickness of a human hair; examination under a transmission electron microscope even requires a sample one thousand times thinner. “We can't cut the samples to size using a saw, which would destroy the coating. Therefore we embed the samples in resin and then grind them down to the desired thickness”, Dr. Klehm explains.
Automatic testing machine quantifies anti-fingerprint effect
Furthermore the researchers are developing an automatic testing machine for the layers. The device is not intended to investigate the particles in the coating, but rather the visibility of the fingerprints themselves. The machine dips a stamp in a solution whose composition resembles that of the oily film on human skin. Working automatically and with constantly identical force and duration, this stamp then presses on the coated surface in order to leave behind “fingerprints”. The machine will use a combination of spectrometric and optical procedures to analyzes how much of the solution remains on the surface and thus to arrive at a percent value indicating the anti-fingerprint effect of the coating. The scientists are currently working to find the ideal combination of analytical equipment for the purpose.
And the researchers have already found a favorite among the various coating systems they have investigated. The task now is to further optimize the system. Development activities should be completed by the end of 2020, when the industrial-scale production of the coating system will be turned over to FEW Chemicals GmbH.
CPCA annual conference
CANADIAN Paint & Coating Association(CPCA) 106th Annual Conference and AGM was held at the Sutton Place Hotel in Vancouver, BC recently. This year's theme was “Canada's Coatings Industry: Vision 20-20 Beyond 2020,” looking at the economic, environmental and social trends of importance to the industry. There will be more challenges for the industry as the government seeks to re-assess chemicals already in commerce as well as new uses of existing chemicals already assessed. Other issues on the agenda were ongoing restrictions coming for biocides, paint waste management and stewardship, new and innovative approaches to sustainability in the industry, and more. Members met at this event to discuss current issues and trends in Canada's coatings industry, and celebrate this year's industry award recipients.
The business sessions addressed some of the challenges faced by the industry today and look in the crystal ball as to what is on the horizon for tomorrow. From ongoing regulatory challenges for coatings products to impressive innovations in the industry and what the coatings industry is doing to ensure products meet the highest standards of performance while respecting human health and the environment.
Highlights included presentations “Economic Update: Trends,Trials and Tribulations” by Dan Murad, President & CEOChemQuest; “Advancing the Interests of Coatings in the UK” by Tania Morrill, marketing director for the British Coatings Federation; and “Global Initiatives – Local Challenges” by Steve Sides, VP, global affairs and chief science officer at the American Coatings Association.
The AGM approved reappointment of four current members to the CPCA Board of Directors.
“The CPCA Board of Directors were reaffirmed at the most recent Annual General Meeting and we are pleased they will continue to provide good governance for the association,” commented Benjamin Moore's Richard Tremblay, the newly elected Board Chair. Mr. Tremblay went on to say that, “The entire Board of Directors were pleased to recognize the tremendous contribution made by Tim Vogel who served as CPCA's Chair over the past four years and we are happy to say he remains on the board as Director.” CPCA continues to focus on new programs and services for members to add value to their respective businesses in Canada.
The 2019 annual Industry Awards Dinner was held at the Royal Vancouver Yacht Club recognizing individual contributions to the Canadian paint and coatings industry. CPCA's highest honor, the Roy Kennedy Outstanding Achievement Award, was presented to Lysane Lavoie, CPCA Director of Regulatory Affairs and Management Information.
The Industry Achievement Award was presented to Fred Veghelyi, OPC Polymers and CPCA Board member and Mannie Cheung, Vice-President, Product Care Association.
The Industry Distinction Award was presented to outstanding individuals who are retiring or recently retired but have made a significant contribution to their companies and the industry generally. These were Mike Lynch (Cloverdale Paint), Luc Pepin (PPG Paints), Steve Wolinsky (Rustoleum), Claude Brosseau (PPG Paints), and Kamlaish Mudhar (Univar). CPCA also recognized important milestone anniversaries of several members as follows: Hero (50 years), Schwartz Chemical (50 years) and Product Care Recycling (25 years).
CPCA's President and CEO, Gary LeRoux commented that: “It was a great conference with important business sessions and the awards dinner held at one of the best locations in Canada, the scenic Royal Vancouver Yacht Club, to honour the achievements of several in our industry.”
Coatings for flexible plastic packaging expected to grow at 4% CAGR
FOOD & Beverage packaging segment is expected to dominate the Flexible Plastic Packaging Coatings Market
The global market for flexible plastic packaging coatings was valued at US$ 1,533.8 Mn in 2017. The market is forecast to expand at a CAGR of 4.0% during the forecast period, 2018-2026.
Coating are generally a phase in which the adhesive is applied to the medium/substrates. Flexible plastic packaging coatings offer consistent high quality finishes as well as provides protection for a wide range of applications. Some of the key coating types readily available in flexible packaging industry are acrylics coating, epoxy coating, urethane & polyurethane coating, etc.
Manufacturers of flexible plastic packaging coating solutions serve almost every end use including food, beverage, cosmetic & personal care, pharmaceuticals industries, among others; thus providing operational advantages as well as improving value for brand owners.
The global market for flexible plastic packaging coatings is segmented as coating type, coating application, substrate type and end use. Flexible plastic packaging coatings can be used over different substrate types which make them preferable for use. Flexible plastic packaging coatings are commonly used in food & beverage packaging sector. Acrylics, urethane & polyurethane and epoxies are some of the most commonly used packaging coatings. This is due to their feasibility to use and provide perfect finish to the product.
Flexible plastic packaging coatings are most commonly used for pharmaceuticals, cosmetics & personal care, chemical packaging and other flexible packaging types. Flexible plastic packaging coatings market is expected to witness maximum revenue from food & beverage segment.
Flexible plastic packaging coatings market is expected to witness high growth in Asia Pacific, it is attributed to the growing packaging industries in the region, especially in countries such as China and India. Although the market is anticipated to dominate by Europe region during the forecast period. In terms of substrate type, polyethylene segment is expected to dominate the global flexible plastic packaging coatings market during the forecast period.
Food & beverage segment of the flexible plastic packaging coatings market was valued at US$ 921.1 Mn in 2017 and is projected to expand at a CAGR of 3.9% during the forecast period 2018-2026.
Market consolidation to intensify the pricing pressure on manufacturers
As the packaging coatings market in the North America as well as the European region are moving towards consolidation, the pricing pressure has started to build up, tightening the profit margin scope for manufacturers. Additionally, the raw materials – both petroleum and non-petroleum based – account for a major share in the overall cost of sales for flexible plastic packaging coatings. The effect of increasing crude oil prices is also expected to be reflected on the petroleum based raw materials, further exaggerating the pricing burden on market players.
Automotive paints and coatings market to hit US$27.5B by 2025
RISING vehicle production coupled with rising consumer preference towards dual color alternatives is driving the automotive paints and coatings market share. Industry players are investing in technologies and finishes to give customers alternatives for customizing their vehicles. Additionally, scratch resistance along with improved gloss finishing and corrosion resistance is gaining significant traction in the market.
Industry participants are collaborating and continuously investing in R&D for developing advanced paint technologies for increasing the market share. For instance, in 2018, BASF entered into a joint venture with Sirrus for developing high-performance automotive coatings based on the methylene malonate technology. These coatings contribute significantly towards lowering emissions and offer smooth finish in vehicles.
The paint industry is collaboratively working with automotive manufacturers to minimize energy consumption and CO2 emission from paint application activities. For instance, in 2017, Audi, BASF, and Covestro entered into a strategic partnership to develop bio-based hardener for Audi Q2. These paints offer superior glossy finishes to the vehicle along with minimizing CO2 emissions significantly.
Polyurethanes accounted for a considerable share in the automotive paints and coatings market. Polyurethanes materials are widely used in paints owing the benefits offered including higher resistance to solvents along with superior mechanical and weathering damage resistance. Industry players are focusing on introducing environmentally friendly polyurethane coatings for improving their market share.
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