Researchers Develop Crack-Resistant Latex Films

TUESDAY, JULY 25, 2023


A team of researchers in Japan, led by Associate Professor Daisuke Suzuki from Shinshu University, has reportedly developed a new way to produce crack-resistant elastic nanoparticle-based latex films without the use of potentially harmful additives.

According to the study, published in the American Chemical Society's journal Langmuir, the new approach could offer advantages over standard methods, while also providing a tough and sustainable latex film. 

About Latex Films

Synthetic latex films are widely used in packaging, biomedicine and electronics, produced by drying out a mixture of polymer nanoparticles and water. As the solvent evaporates, the nanoparticles reportedly become more packed until the interactions between polymer chains at the boundaries of nanoparticles create a “coherent” film.

Latex films produced this way are reportedly often weak and, in most cases, organic solvents and fillers must be added to improve the mechanical properties. These additives are reportedly not only expensive, but also harmful to the environment.

According to a report, the key to the team’s approach was a novel molecular structure called rotaxane, which comprised two main components—a ring-like molecule and a linear axle molecule. The ring-like molecule is reportedly threaded through the axle molecule, which then becomes mechanically trapped due to the shape of the axle terminations.

The researchers stated to have leveraged this interlocking mechanism in rotaxane by making the ring-like molecule chemically bind to one polymer chain and the axle molecule to another one. Then, the researchers reportedly prepared mixtures of water and polymer nanoparticles through “standard ultrasonication,” and subsequent polymerization that then was used to produce thelatex films.

Researchers stated that the stretching experiments performed on these films showed that the rotaxane-based strategy resulted in “remarkable properties.”

"In contrast to conventional nanoparticle-based elastic polymers, the latex films composed of the rotaxane-crosslinked nanoparticles exhibited unusual crack propagation behavior," explained Dr. Suzuki. "The direction of crack propagation changed from being parallel to the crack to one perpendicular to the crack, resulting in an increased tear resistance."

The published development also reportedly included contributions from Yuma Sasaki from Shinshu University, as well as Professor Toshikazu Takata from Hiroshima University.

The team reportedly expects their work to broaden the scope for the design of new polymer films without the use of additives. They state that these materials could be made to be biocompatible, with potential applications in biotechnology and medicine in addition to packaging, industrial coatings and adhesives.

"They are degradable and can be easily disassembled into individual nanoparticles by simply soaking them in an environmentally friendly organic solvent, such as an aqueous ethanol solution," said Dr. Suzuki. "These nanoparticles can then form a film again upon evaporation of the solution. The findings of this research can thus help create highly durable and recyclable materials."

Similar News

In February, researchers at Cornell University announced an all-dry polymerization technique which uses reactive vapors to create thin films with enhanced mechanical strength, kinetics and morphology.

The researchers stated that this method can be applied to various methacrylate and vinyl monomers for polymer coatings, including in microelectronics, antifouling for ship hulls or separation membranes for wastewater treatment purification.

The research was published in the journal Nature Synthesis. The lead author is doctoral student Pengyu Chen, alongside co-senior authors Rong Yang, assistant professor in the Smith School of Chemical and Biomolecular Engineering in Cornell Engineering; and Jingjie Yeo, assistant professor in the Sibley School of Mechanical and Aerospace Engineering. 

According to the university, Yang’s lab studies how vapor-deposited polymers interact with bacterial pathogens and how bacteria then colonize polymeric coatings in paint or biomedical devices, for example. The team then wanted to develop a different approach to diversify chemical vapor deposition (CVD) polymers by using a “magic” solvent, or inert vapor molecule.

The solvent is reportedly not incorporated into the final material but interacts to produce new material properties at room temperature. Yang describes this “old chemistry but with new features.”

The solvent, Cornell reports, interacted with a common CVD monomer via hydrogen-bonding.

The lab then simulated the molecular dynamics behind the solvent and monomer interaction, as well as how their stoichiometry could be tuned.

Nanoindentation testing was then conducted on the resulting thin film, finding that the solvation mechanism had strengthened the material. The solvent also reportedly caused the polymer coating to grow faster and change its morphology.

Co-authors also included Shefford Baker, associate professor of materials science and engineering, Zheyuan Zhang and Zach Rouse. The study was conducted at the Cornell Center for Materials Research.

The research was supported by the National Science Foundation, the U.S. Department of the Navy’s Office of Naval Research and the Fleming Scholarship.

   

Tagged categories: Additives; Asia Pacific; Bioproducts; Coating Materials; Coating/Film Thickness; Coatings; EMEA (Europe, Middle East and Africa); Environmental Control; Environmental Protection; Green coatings; Latex; Latin America; North America; Polymers; Sustainability; Tools & Equipment; Z-Continents

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