While the viscosity value is itself important, the rheologic character of the product, both in the bottle and during utilization, must also be considered.
Many polymers are commercially available to produce the desired rheologic character.
Selection of a polymer is based on biological compatibility and absence of undesired interactions with other ingredients as well as rheology. We have found a semi-logarithmic relationship between sedimentation rate and polymer concentration. Another property sometimes exhibited by polymers is flocculation of dispersed particles in certain systems. In any case, the formulator must be aware of the possibility that viscosity builders may induce changes in other physical properties. Several important applications depend on the development of rheological structure in situ.