Manufacturing

Shampoos, paints, lubricants, and other commonly used "complex fluids" and soft materials have remarkable properties. Shampoo in a pump dispenser must be thick enough to stay in your hand, yet be thin enough to pump easily from the dispenser and spread into your hair. The key to these properties is shear thinning—applying a force in one direction to make thick become thin (like spreading soap solution by rubbing your hands together). How the molecular structure of a complex fluid changes during shear thinning can be seen using neutrons. When the material is thick, the molecules are tangled, but when a one-directional force is applied (e.g., by a paint brush), the molecules become ordered under flow, making the material thin. Research at SNS could lead to development of better complex fluids and soft materials used in the manufacturing industry.

Paint is another example of a complex fluid whose change in molecular structure during shear thinning can be studied with neutrons. To work well, paint must be both thick enough to stick to your brush and thin enough to spread smoothly over a wall.

A related area of study is microemulsions (droplets of one liquid dispersed in another). Microemulsions are used, for example, in food processing and cosmetics products, lubricants, and additives that control industrial processes. Neutron research could also lead to advancements in the study of elastic materials, such as rubber.

In addition, structural information from neutron-scattering studies has aided in the improvement of many manufactured materials we use every day, such as:

Neutron scattering has guided the development of giant molecules that make up synthetic fibers for clothes.

• drugs
• plastics
• cosmetics
• synthetic fibers for clothes
• healthier foods
• new materials for buildings, cars, and aircraft
• better lubricants for machines