Figure 11.
A cartoon representation highlighting the thermal behavior of the aqueous PAD as a function of temperature. In the figure, spheres denote water molecules, black lines denote PAD chains and red is used to indicate restricted motion of the polymer chains due to inter-chain interactions, such as nodes. As described in the text, near 20 °C, polymer chain nodes are present and surrounding water has only one nearly isotropic dynamical characteristic over the time scale of the measured T1 and T2 relaxation times (refer to Figure 8). With increasing temperature, polymer chain nodes are broken due to thermal agitation resulting in the formation of a gel characterized by a network of PAD molecules with at least three interspersed reservoirs of water characterized by different dynamical characteristics (refer to Figure 8). At 70 °C only two water reservoirs are observed that do not exchange (refer again to Figures 8 and10).