Free movable water

FIGURES./ NMR data processing—principle. Measured data are in a time domain. The inversion process results in a partitioning of the individual relaxation contributions (bulk volumes) with the three regions clay-bound water (CBW), capillary-bound or immovable water (BVl), and free movable water (BVW). Regions are separated by cut-offs. 

All surface-active molecules, such as soaps and lipids, can be prepared as monomolecular layers at the air-water interface. Driven by the reduction of the surface free energy of water, these molecules spread when applied to the surface, for example, from a volatile solvent (Fig. 10). The physical properties of these monolayers were first investigated in the 1940s by Langmuir after his first work on molecules in insoluble monolayers [41]. A so-called Langmuir trough filled with water defines an exactly known area for the spread molecules (Fig. 10). At low lateral density, these molecules behave like a quasi-two-dimensional gas. If the area for these molecules is reduced by a movable barrier, this lateral compression will eventually lead to a measurable lateral pressure n (force F per unit length of barrier). Which can be measured by a so-called Wilhelmy balance (see Kuhn et al. [42]), It is the difference between the surface tension of the free, y, and the layer-covered, y, water surface ... 

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