Electrical Fluctuations Around a Charged Colloidal Cylinder in an Electrolyte
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In Chap. 2 we developed a method to determine the natural electrical thermal fluctuations and their spectral distribution across two points in the neighbourhood of a spherical electrically charged particles immersed in an ionic solution. The essence of the method is to consider the charged sphere with its surrounding ionic atmosphere as a capacitor and a resistor in parallel.
In this chapter we apply this method to estimate the electrical fluctuations (field and potential) around rod-like rigid polyelectrolyte bearing a uniform surface charge distribution dispersed in an aqueous salt solution of pointlike ions. We performed computer simulations to solve the Poisson–Boltzmann (P-B) equation and also developed formulas to calculate the fluctuations in the case of a low potential, Debye–Hückel approximation (linearized P-B equation). We apply the formalism to a DNA solution which is a well-known model for a biopolymer. They are shown plots of the potential and electric field fluctuations as a function of the Debye–Hückel length, κ−1, and distance, d, from the polyelectrolyte surface for several molecular sizes.
KeywordsElectrical fluctuations Cylindrical polyelectrolytes
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