Dielectric analysis of poly(diallyldimethylammonium chloride) aqueous solution coupled with scaling approach

Abstract

Dielectric measurements were carried out on aqueous solution of poly(diallyldimethylammonium chloride) (PDADMAC) with different concentrations at room temperature. Additionally, for selected solutions the temperature dependence of dielectric relaxation spectroscopy (DRS) was examined in the range of 5-70 degrees C. The dielectric relaxation in the order of around MHz was observed, and the dielectric parameters were determined from the dielectric spectra by fitting data with the Cole-Cole equation. The dielectric parameters showed strong dependences on concentration and on temperature, respectively, and these dependences are analyzed by the scaling theory. From the analysis of concentration dependence of dielectric parameters, the dielectric relaxation is assigned to the localized fluctuation of uncondensed counter-ions over the distance between chains in dilute solution and correlation length in semi-dilute solution, respectively, and the solvent quality parameter for the uncharged polyelectrolyte chain is evaluated. By the analysis of temperature dependence of dielectric parameters, we find that: the physical meanings of the typical lengths of uncondensed counter-ions are not influenced by temperature; in semi-dilute solution, the highly extended length of the chain (correlation length) increases and the end-to-end distance of the chain decreases with increasing solution temperature; in the change process of dielectric relaxation of PDADMAC solution induced by the increase of temperature, the increment of ionic diffusion coefficient and decrement of permittivity of the solvent medium are the major factors. The enthalpy and entropy of activation of the dielectric relaxation are experimentally determined by the dependence of relaxation time on temperature, individually.

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

“…Dynamic behavior of polyelectrolyte solutions, which depend on the structure, conformation of chains, and electrostatic interaction, have attracted increasing attention. − The strong electrostatic interactions between charges, which are the most typical characteristic of polyelectrolyte, lead to the various behaviors, such as complex chain conformation and charge distribution of polyelectrolyte solutions. Because the electrostatic interactions and dynamics of polyelectrolyte solutions can be described by charge distribution model or ion–dipole interaction, dielectric relaxation spectroscopy (DRS) method is increasingly used for characterizing these interactions, motion of the main or branched chain, and the fluctuation of counterions. − We have studied the dynamic behaviors of chitosan, a typical biological macromolecule, and poly(diallyldimethylammonium chloride) (PDADMAC) solutions by dielectric spectroscopy coupled with scaling approach. − In addition, the studies of charged side-chain dynamics in polyelectrolyte aqueous solutions were also reported. For example, the existence of a dielectric dispersion in aqueous solutions of poly( l -glutamic acid) in a region around 100 MHz, attributable to internal motions of the polar groups of the side chains, has been reported by Mashimo et al and this was later confirmed by Bordi et al Moreover, the microdynamics of the side chains of poly(lysine) and chitosan derivatives were also reported. , The above studies showed that DRS is useful for exploring microdynamic information of the charged short side chain in polyelectrolyte solution.…”

Anomalous Debye-like dielectric relaxation of water in micro-sized confined polymeric systems

“…These processes are characterized by a relaxation time and a dielectric increment proportional to the square of a typical length connected to the distance between polymer chains. 16,[35][36][37] In the present case, for a set of reasonable values of the parameters, this mechanism should produce a dielectric relaxation of only few dielectric units and, moreover, falling at relatively high frequencies (of the order of 100 MHz). Therefore, this possible polarization mechanism must also be ruled out.…”

Dielectric Behavior and Phase Behavior of Block Copolymer PEO13-PPO30-PEO13 Aqueous Solution

“…In addition, there are many studies on the macroscopic mechanical properties of block polymers such as viscoelasticity and rheology. ,,, Alternatively, dielectric spectroscopy can be used to measure the interaction of electromagnetic fields and matter and has also been used to study the polymer structure and dynamics behavior. The validity of the dielectric spectroscopy for polymer solution systems has long been recognized and reported by a large number of research. − In recent years, we also studied the chain conformation of polyelectrolyte solution − and the microstructure and phase transition dynamics of microgel suspension − by dielectric spectroscopy. Dielectric studies on block polymers have also been reported for the past decade or so, and most studies have focused on the chain dynamics of block copolymers. − However, the study on the micellization behavior of block copolymers in solution is relatively less.…”