On further cooling past 30 C (Fig. 1) the rapid increase in viscosity
slows, and further increases are much more gradual for all of
the applied shear rates. This observed change in viscosity could be a
result of further ordering of a small number of remaining disordered
polymer chains within the particles and/or at their surface;
conformational ordering persists even at temperatures much lower
than the gelling temperature. This would be expected to slightly
increase the size of the particles and thus the viscosity during their
production. Additionally, the observed behaviour could be a
consequence of the inter-particle interactions that take place as a
result of the presence of disordered charged polymer chains at their
surface (Norton et al., 1998) which likely bind to free ions in the