UMass Amherst Scientists Make Polymers Containing Solid Nanoparticles

AMHERST — Two scientists at UMass Amherst are building a new class of environmentally friendly polymer materials (or polymer-based fluids) called complex coacervates that will contain solid nanoparticles. Supported by a three-year, $357,694 grant from the National Science Foundation, they also will uncover and chronicle the design rules for these materials, creating a road map for further research in the field. 

Sarah Perry, chemical engineering, and Maria Santore, polymer science and engineering, say coacervates are well-known to scientists, but that it is not well-known how extensively they can be modified for new uses. They also say there are no systematic and comprehensive rules for building these materials, so they will create these so-called rules of thumb for other researchers to follow.

Perry says coacervates have been around for decades, but there hasn’t been a concentrated effort to discover a wider range of applications. She says scientists tend to create these materials for a specific use but haven’t explored how complex or how sophisticated they can be.

“We expect the complexation of nanoparticles and microparticles with polymers will broaden the mechanisms involved in coacervate formation, enabling the creation of entirely new materials,” Santore said. “Particle-containing coacervates have the potential to radically advance a range of fields from coatings to vaccine formulation. We’re excited to learn the range of particles that can be incorporated in coacervates.”

Coacervates, complexes of oppositely charged polymers that have separated into two liquid phases due to electrostatic forces, are commonly used in coatings, adhesives, pharmaceuticals, and cosmetics. In food products, they are used to encapsulate flavors and additives, and as a way of controlling the ‘feel’ of the product. They are also found in nature, where underwater animals use them to make natural adhesives.

Santore says a key element of this research is working with environmentally friendly, water-based systems. This has implications for the food and medical industries, where the delivery of specific nanoparticle materials, including drugs, would be possible. Some nanoparticles can also be used for diagnostic purposes.

“Our goal of developing a robust and universal framework for designing coacervates containing particles ranging in size from single molecules to living cells represents a grand challenge in materials science,” Perry said. “The complexity of these systems is precisely why our kind of collaborative efforts are so critical.”

Santore and Perry say they plan to build new types of the polymers using different sizes and shapes of nanoparticles and different lengths of polymer strands. They will also look at where the solid particle is placed on the polymer chain and how that affects its structure and function.