(NIST: Gaithersburg, MD) -- Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a microminiaturized device that can perform complex viscosity measurements—critical data for a wide variety of fields dealing with things that have to flow—on sample sizes as small as a few nanoliters. Currently a table-top prototype, the NIST rheometer could be a particularly valuable tool for biotechnologists studying minute quantities of complex materials that must function in confined spaces.

Viscosity, elasticity, and how materials flow when subject to a force is the subject of rheology, and the measurements can tell a lot about a complicated material such as a gel. Is it more like a liquid or a solid? By how much and under what conditions? The popular toy Silly Putty is a classic example of complex viscoelasticity, bouncing better than a rubber ball under a sharp, sudden force but slumping into a puddle when left alone.

 …