Counterion distribution monitoring

Counterion distribution monitoring (CDM) can determine, in real time, when the coupling reaction is complete [24]. It uses an in-line UV detector and is most sensitive in the region where the coupling reaction is approaching completion. 

Surface forces measurement is a unique tool for surface characterization. It can directly monitor the distance (D) dependence of surface properties, which is difficult to obtain by other techniques. One of the simplest examples is the case of the electric double-layer force. The repulsion observed between charged surfaces describes the counterion distribution in the vicinity of surfaces and is known as the electric double-layer force (repulsion). In a similar manner, we should be able to study various, more complex surface phenomena and obtain new insight into them. Indeed, based on observation by surface forces measurement and Fourier transform infrared (FTIR) spectroscopy, we have found the formation of a novel molecular architecture, an alcohol macrocluster, at the solid-liquid interface. 

In order to explain the temperature behavior of s far below the percolation onset a simple statistical model of polarization of nanometer-sized droplets containing negatively charged ions at the interface and positive counterions distributed in the droplet interior was developed (5,117). In the framework of this model, when the values of the droplet size and the constant of dissociation of ionic surfactant are both small, an experimentally monitored temperature increase in s can be explained by the temperature growth of the mean-square fluctuation dipole moment of a droplet. 

Counterion binding is not a well defined quantity, with various experimental techniques weighing the ion distribution slightly differently. Thermodynamic methods (e.g. ion activities or osmotic coefficients) monitor the free counterion concentration, transport methods (e.g. ion self diffusion or conductivity) the counterions diffusing with the micelle, and spectroscopic methods (e.g. NMR) the counterions in close contact with the micelle surface. Measurement of the effect of Na+ counterions on the symmetric S-O stretching modes would also be expected to be highly dependent on the distance of the counterion from the micelle surface (similar to the NMR method). 

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