Microfluidic Flows of Viscoelastic Fluids

This chapter provides an overview of viscoelastic fluid flow at the microscale. It also provides the problem of mixing at the microscale and of the current methods used to tackle this problem. The chapter presents an introduction to non-Newtonian viscoelastic fluids describing their most relevant rheological properties. It explains the governing equations for Newtonian and non- Newtonian fluid flow, including the constitutive equations that describe the rheology of the fluids. The chapter deals with passive mixing methods in viscoelastic fluid flows and other forcing methods for promoting viscoelastic fluid flow at the microscale are briefly reviewed. Flow systems built around microfluidics are becoming increasingly popular in a wide range of industrial applications dealing with both gas and liquids. They associate low production costs with low power consumption and waste reduction, allow for easy integration with electronics toward lab-on-a-chip devices, but require demanding manufacturing facilities and highly efficient signal detection systems. Controlled Vocabulary Terms lab-on-a-chip; microfluidics; non-Newtonian fluids; signal detection; viscoelasticity