Viscometric Study of PEG-400 in Aqueous and Non Aqueous

The increase in the viscosity with lower temperatures is particularly noticeable within super cooled water. The water cluster equilibrium shifts towards the more open structure as the temperature is lowered. This structure is formed by stronger hydrogen bonding. in turn this creates lager clusters and reduces the ease of movement (increase viscosity), so reducing the strength of the hydrogen bonding network, which is also partially responsible for the viscosity. This reduction in cohesiveness more than compensates for the reduce void volume. It is thus a direct consequence of the balance between hydrogen bonding effects and the Vander Waals dispersion forces in water; hydrogen bonding prevailing at lower temperature and pressure.