Researchers at The University of Illinois at Chicago has developed a line of coatings for industrial surfaces that use a specialized chemical composition to retard ice formation. This can help protect contents such as vaccines that freeze inside vials during ultra-cold chain transport, thereby maintaining their effectiveness.
Dr. Rukmava Chatterjee, one of the researchers involved in creating the coatings, explains how they can be used to complement multiple packaging applications throughout the supply chain while providing a lower environmental footprint than conventional coatings. typical antifreeze alternatives.
The impetus for antifreeze solutions
“Cold storage unit supply chain management is essential for various industries ranging from healthcare to food,” Chatterjee explains. “Whether it’s the delicate cut of Wagyu beef or the critical COVID-19 vaccine, most items have a limited shelf life, require proper packaging and storage at tightly controlled temperatures from manufacture through to that they reach the end user; a critical task performed by a global network of transport and storage facilities.
However, the complexity of global supply chains and the intensive demands of some forms of transportation can lead to what Chatterjee identifies as “inherent system issues” involving temperature fluctuations of the products themselves. Freezing of products inside packaging can impair their integrity, while accumulation of ice on the internal or external surfaces of containers and vehicles can impair their operation and safety.
While some solutions, such as superhydrophobic surfaces and lubricants, have been developed, the research paper authored by Chatterjee and his research partners, Hassan Bararnia and Sushant Anand, notes significant drawbacks to these technologies, such as their inability to cope with high humidity and how quickly they can be removed by shearing forces, making them temporary. According to Chatterjee, “The capital market for anti-icing and ice-repellent materials is worth $20 billion per year. Unfortunately, most commonly used passive ice removal techniques incur high manufacturing costs or suffer from poor long-term durability.
This apparently means that “energy-intensive” and “negative environmental footprint” active solutions, such as chemical de-icing and mechanical scraping, continue to be favored by the industry. Therefore, while “technologies that can delay the formation of ice/frost on surfaces or facilitate its passive removal play a central role in industrial applications operating in frigid climates”, Chatterjee and colleagues identified a gap in the market for sustainable solutions with minimal environmental impact. repercussions.
Chatterjee’s research team has “formulated an extensive library of over eighty compositions with superior freeze protection properties”. The major component of the coatings is dimethyl sulfoxide (DMSO), which Chatterjee identifies as “a biocompatible cryoprotectant that can be securely enclosed in a polymer matrix, giving it increased resistance against dissolution and shearing off.” Chatterjee adds that DMSO is a “well-known industrial solvent” derived from wood.
For the researchers’ antifreeze gels, a variant that Chatterjee says is among “our most successful coatings” includes only one component other than DMSO: gelatin. “Gelatin, as you know, is used to make a variety of desserts [and] puddings,” notes Chatterjee. “Therefore, all coating materials are biological in nature and are not expected to have any adverse effect on the environment.”
According to Chatterjee, the coatings “work by taking advantage of certain heat-sensitive properties, allowing them to generate a slippery lubricating layer on their surface that acts as a protective barrier against contaminants ranging from tiny bacteria to large-scale gel.” This means that the coatings are “multifunctional by design”.
Compared to untreated industrial metal surfaces, such as aluminum, the researchers’ coatings could delay ice formation about 87 times longer and facilitate ice removal about 665 times. Chatterjee says this sets the liners apart as “a complete game changer compared to most commercial liners available in today’s market.”
The multifunctional nature of the coatings developed by the team at the University of Illinois at Chicago makes them suitable for a range of applications, which can, in turn, help packaging ensure product safety throughout. of the supply chain.
For vaccines, temperature fluctuations during storage and shipping can compromise their “nutritional value or immunological potency, potentially resulting in multi-billion dollar financial losses” in the event they are deemed unusable and destroyed, Chatterjee says. . “A widespread problem that occurs during storage under such cryogenic conditions is the accidental freezing of the internal contents of the drugs/vaccines themselves in the cold chain. For example, guidelines from the World Health Organization (WHO ) state that adjuvant vaccines (eg, hepatitis B vaccine) should not be subjected to freezing temperatures.
Similarly, the accumulation of ice on the internal surface of secondary packaging such as cold chain storage boxes can make it difficult to detach or retrieve products from the inside. The surface of the packaging could also be damaged in the process of separating the ice buildup, again compromising the product inside. In the case of frozen foods packaged in flexible plastic packaging, for example, a tear in the surface acquired during transport could mean that they fail quality control and do not reach the shelves, causing both loss of money and food waste.
Additionally, some of the coatings also have antibacterial properties. Chatterjee cites the example of a coating that can simultaneously “prevent a smartwatch battery from dying in the freezing winter” and “prevent bacterial contamination.” As part of their research, Chatterjee’s team demonstrated that there was no accumulation of e. coli on the coated surface of the smartwatch compared to an uncoated control over a period of seven days. This feature could also lend itself to food packaging, with antimicrobial food coatings being a rapidly growing research and development segment worldwide. “Additionally, it can also be used in the healthcare/pharmaceutical industries seeking antibacterial coatings,” Chatterjee notes.
Coatings also work on a larger scale to protect vehicles such as aircraft or energy infrastructure such as wind turbines, both of which are critical to packaging as an energy-intensive industry with complex supply chains. and complete. “The versatile nature of their performance attributes makes them applicable to a wide range of industries, especially those requiring advanced winterization and freeze protection,” Chatterjee tells us. “So our coatings can typically be used in industries operating during the winter season: aerospace, wind turbines, off-shore oil rigs, ships, automobiles, power transmission lines, HVAC, cold chains for vaccines, building infrastructure, etc.”
The use of coatings by Chatterjee and his research colleagues can therefore improve the protection of sensitive products, particularly for the pharmaceutical and food sectors, as they move through the supply chain, improving the function of the packaging or preventing it from being damaged.
Coatings are gaining traction in the industry, with the solution featured on the cover of the academic journal Advanced Materials earlier this month. Chatterjee notes that his team has also been approached by North American companies, including the CNN Tower in Toronto and the Mount Washington Weather Station Observatory in New Hampshire, who “regularly struggle with heavy icing/icing in their equipment installed and spend billions of dollars every year. in thermal defrosting”.
“Because of the versatile commercial applications, we have filed a worldwide patent application titled ‘Compositions and Methods for Inhibiting Ice Formation on Surfaces’ with the UIC Office of Technology Management,” adds Chatterjee.
Overall, the next steps for the coatings include “making even more durable gels and testing them in real-world applications as described above to solve real-world problems, and thus transition to a sustainable future.”