We examine the bending of an Alexander–de Gennes polymer brush over a wide range of curvature from weak to strong. Two different models are used, a blob model and a simpler Flory mean field model. In both cases the height change upon bending is anomalous. In the case of a blob model the height increases for weak bending. In the Flory model there is no height change to first order in the curvatu...

This chapter summarizes the thermodynamics of multicomponent polymer systems, with special emphasis on polymer blends and mixtures. After a brief introduction of the relevant thermodynamic principles – laws of thermodynamics, definitions, and interrelations of thermodynamic variables and potentials – selected theories of liquid and polymer mixtures are provided: Specifically, both lattice theor...

2014 We develop a Flory theory for the problem of conductivity in a d-dimensional random resistor network. We find that the conductivity exponent t is related to the fractal dimensionality df according to the Alexander-Orbach conjecture t = d 2 + df/2, where consistently with Flory theory df = (d + 2)/2 for percolation and df = 2(d + 2)/5 for lattice animals. The results are in excellent agreem...

The thermodynamic equilibrium between charged colloids and an electrolyte reservoir is named after Frederic Donnan who first published on it one century ago (Donnan 1911 Z. Electrochem. 17 572). One of the intriguing features of the Donnan equilibrium is the ensuing osmotic equation of state which is a nonlinear one, even when both colloids and ions obey Van 't Hoff's ideal osmotic pressure law...

The Flory theory for a single polymer chain is derived as the lowest order of a cumulant expansion. In this approach, the full original Flory free energy (including the logarithmic term), is recovered. The prefactors of the elastic and repulsive energy are calculated from the microscopic parameters. The method can be applied to other types of monomer-monomer interactions, and the case of a sing...

We introduce a comprehensive model of a mucin-like polyelectrolyte gel swelling-deswelling which includes the ion-mediated crosslinking of polymer strands and the exchange of divalent and monovalent ions in the gel. The gel is modeled as a multi-phase mixture which accounts for the polymer and solvent volume fractions and velocities as well as ionic species concentrations. Motion is determined ...

The swelling behavior of acrylamide (AAm)–based polyampholyte hydrogels in water and in aqueous salt (NaCl) solutions was investigated. [(Methacrylamido)propyl]trimethyl-ammonium chloride (MAPTAC) and acrylic acid (AAc) were used as the ionic comonomer in the hydrogel preparation. Three sets of hydrogels containing 70 mol% AAm and 30 mol% ionic comonomers of varying mole ratios were prepared. T...

Free metal ions in aqueous and terrestrial systems strongly influence bioavailability and toxicity. Most analytical techniques determine the total metal concentration, including the metal ions bound by dissolved organic matter. Ion activity can be measured with ion-specific electrodes (ISEs) for some metals, but an electrode for Zn is not commercially available. As a result, very few data are a...