Rheological Properties of Acrylamide Hydrogels

Using Optical Tweezers for the Characterization of Polyelectrolyte Solutions with Very Low Viscoelasticity

“…In this context, polyacrylamide (PAM) is a commonly used polyelectrolyte, with applications that range from biology − to industries such as oil processing, purification of natural water and wastewater, and paper making . Several literature studies concerning different methods for the preparation of polyacrylamide solutions − and the influence on their rheological properties of different parameters such as polymer concentration, solvent composition, temperature, − and aging of the sample have been reported . In these cases, the rheological properties of PAM, in common with other water-based solutions of polyelectrolytes, are usually studied with conventional bulk rheometers and can be described by means of frequency-dependent complex shear modulus G* (ω) = G ′(ω) + i G ″(ω), where the real part (i.e., the elastic modulus G ′(ω)) provides a measure of the energy stored by the solution and the imaginary part (i.e., the viscous modulus G ″(ω)) provides a measure of the energy dissipated by the solution in response to the work exerted by an external force.…”