Sander Woutersen
Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, Netherlands
The two simplest polyethers are PEG (repeating unit -CH2-CH2-O-), which is present in almost every cosmetic, and POM (repeating unit -CH2-O-), a plastic known to every (former) chemistry student as the brightly-coloured Keck clips for connecting glassware. Surprisingly, PEG dissolves very well in water, but POM is completely insoluble: the opposite of what one might expect from the ratio of hydrophobic to hydrophilic parts in these polymers. Similar differences in solubility exist for the oligomers. By investigating the dynamics of water in polyether solutions using spectroscopic experiments in combination with ab-initio calculations and simulations, we try to solve this apparent mystery. In the second part of the talk, we will have a look at "biological water". Cells are extremely crowded, and to what extent this affects the properties of intracellular water is heavily debated. Using time-resolved vibrational and dielectric-relaxation spectroscopy we observe the random orientational motion of water molecules inside living cells of three prototypical organisms, and investigate how the dynamics of "biological water" differs from that of "normal" water.