Rheology is the study of the flow and deformation of complex or soft materials—materials that exist somewhere on the spectrum between fluid and solid. Though this may sound exotic, we all interact with these sorts of materials on a daily basis: toothpaste, peanut butter, and even the blood flowing through our veins are rheologically complex materials.

The scientific discipline of rheology is relevant to nearly all studies of material properties. It is a key tool and perspective for understanding a wide variety of materials applications and industries.

The big picture of rheology is about understanding the relationships between a material's complicated microstructure and its behavior on the macroscale. For example, a rheologist in the food industry might assist with designing a new food product by identifying ingredients with promising properties, helping set processing parameters to maintain a consistent product, or designing quality control measurements to ensure that the product has a consumer-approved texture.

At the same time, an engineer working in mining or construction might need to design a pumping system for slurries or pastes. In that case, understanding the rheology of these mixtures is important to ensure they reach their intended destination.

No matter the industry—food, pharmaceuticals, cosmetics and personal care products, paints and coatings, polymers, and adhesives—rheology is about linking a material's physical material properties to the way it will behave in situations across the spectrum, from initial formulation to the manufacturing plant to consumer interactions. Despite the huge variety of applications, there is often significant common ground among the underlying physical concepts which govern the microstructural interactions of polymers, gels, emulsions, particle suspensions, and other materials.

There is no single path to a career in rheology or soft material physics. Practitioners of rheological methods have backgrounds in physics, chemical engineering, chemistry, food technology, materials science, pharmaceutical engineering, biology, and mechanical engineering, among other areas. Knowledge of rheology often complements other physical characterization or computational methods in these practitioners’ toolboxes. Undergraduate courses on fluid flow, solid mechanics, and materials characterization often provide good foundational knowledge related to rheology.

At large companies handling many different materials development projects, an expert in rheology typically has a graduate degree in one of the aforementioned programs. It is not unusual for people pursuing higher education related to rheology to shift their careers and change the area in which they apply their knowledge. For example, someone who studied polymer rheology during their PhD in a chemical engineering program might pursue a career focused on food rheology. While some people who work in rheology have “rheologist” in their job title, job titles like research specialist, research scientist, product specialist, and quality engineer are more common.

To learn more about the exciting opportunities in academia, industry, and government for people who study and apply rheological theories and methods, consider attending a Society of Rheology meeting. Meeting information is available at rheology.org.

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About the Author

Arif Z. Nelson is an assistant professor at the Singapore Institute of Technology. He studies applications of soft materials across the industries of sustainable food systems, pharmaceuticals, and other formulated products. Among other efforts to translate research into more impactful applied learning practices, Nelson also maintains a website about cooking in the context of soft materials and rheology at the Soft Matter Kitchen, arif.zone/home/kitchen. Tiramisu, anyone?

The Society of Rheology

The Society of Rheology (SOR) aims to expand the knowledge and practice of rheology through education, partnership, and collaboration with associated fields, industries, and organizations, as well as to share rheology and its impacts. To learn more, visit rheology.org.

SPS members are eligible for a free year in SOR when they register or renew. For details, visit spsnational.org/about/
membership/free-ms-membership.

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