RheoSense Inc. recently introduced the latest addition to its VROC family of viscometers with the e-VROC. The new viscometer provides extensional viscosity data by monitoring the sample flow through a microfluidic contraction within the measuring cell.
The system measures the pressure upstream and downstream of a contraction using pressure sensors and registers changes in the flow. The fluid undergoes an almost constant extension through the contraction/expansion, enabling the calculation of the extensional viscosity.
The advantage of this approach is that shear-rate-dependent viscosity and extensional viscosity can be provided at a specific temperature within the same measurement.
The e-VROC chip is engineered with a microfluid channel of uniform width and depth. It has a hyperbolic contraction/expansion zone in the middle of the channel and four monolithically integrated pressure sensors (two in the upstream and two in the downstream of the contraction/expansion zone). A liquid entering the channel first experiences shear flow in the straight channel and then a uniform extension in the contraction zone.
The e-VROC is ideal for polymer applications or for fluids with certain extensional viscosity properties similar to those that are used as additives to prevent mists from forming in volatile fluids like jet fuel or for turbulent drag reduction in oil pipelines and sewer systems. It can also be used in other applications including spraying, electrospinning, enhanced oil recovery and food processing.
For more information, visit www.RheoSense.com.