Counter ions, binding

This volume covers the structural relations between thermotropic and lyotropic liquid crystals (Chapters 1 and 2) and compares them with the micellar systems (Chapter 3). The interfacial aspects and the accompanying stability problems are covered in Chapters 5 and 6. The molecular dynamics in liquid crystals, the importance of water structure and of counter-ion binding for their stability are three essential factors for long range order systems, which are treated in Chapters 7, 8, and 9. The final chapter by E. J. Ambrose illustrates the change of order in a biological system under malignant conditions. 

A charged molecule in high dielectric medium (water) experiences image forces at an interface towards low dielectric medium (hydrocarbon, air) [41]. This favors counter-ion binding, hence the polyelectrolyte is not charged near the interface. 

Surfactant mw dalt. 8) % temp °C CMC M medium molar vol. L/mole aggr. numb Kr. or Cl. pt. C counter ion binding ref name... 

The results in polar solvents, other than water, indicate that self-assembly is much less cooperative. Consequently, the degree of counter-ion binding is also lower. 

Surfactant adsorption close to the c.m.c. may appear Langmuirian, although this does not automatically imply a simple orientation. For example, rearrangement from horizontal to vertical orientation or electrostatic interaction and counter ion binding may be masked by simple adsorption isotherms. Therefore, adsorption isotherms must be combined with other techniques such as microcalorimetry and various spectroscopic methods to obtain a full picture of surfactant adsorption. 

Fig. 2 Concentration dependence of the degree of counter-ion bind-Fig. 1 SAXS scattering curve of CsPFO in H2O (100 mM). The ing and the aggregation number (m) obtained from the analysis of...

Watanabe, A., M. Matsumoto, H. Tamai, and R. Gotoh, ElectrocapiUary phenomena at oil-water interfaces. Part 2. Counter ions binding at oil-water interfaces, Kolloid Z ZPolym, Vol. 221, (1967) p. 47. 

Dutta, P. (2000) What X-rays teU us about the ordering of molecular and counter ion binding strength are found to decrease as the chain backbones in Langmuir monolayers. Colloids Surf. A, 171, 59-63. 

The force acting between fixed charges on polyion and counter-ions is not unique but varies with combination of counter-ion and fixed group. Therefore, the cause for counter-ion binding may depend on the ionic species. 

Kotin and Nagasawa [6] defined the counter-ion binding in analogy to the definition of Bjerrum on ion-pair formation [36]. That is, it is assumed that a polyion is placed in an infinite volume of a neutral salt solution of uni-uni valent type and the polyion is a rod of infinite length having a charge density N/L, Moreover, it is assumed that the ionic distribution around the rod is determined from the Poisson-Boltzmann equation. Then, if one plots the distribution of counter-ions PcC ) against the distance from the axis of the polyion r,... 

Apparent molal volumes of polyelectrolytes and volume changes upon counter-ion binding... 

Similar work has been done [5] in an investigation of counter-ion binding by poly-(jTiethacrylic acid), PMA, and poly(acrylic acid), PAA. 

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