Dielectric relaxations and conduction mechanisms in polyether–clay composite polymer electrolytes under high carbon dioxide pressure

Abstract

The composite material P(EO/EM)-Sa consisting of synthetic saponite (Sa) dispersed in poly[ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidyl ether] (P(EO/EM)) is studied by "in situ" measurements using broadband electrical spectroscopy (BES) under pressurized CO2 to characterize the dynamic behavior of conductivity and the dielectric relaxations of the ion host polymer matrix. It is revealed that there are three dielectric relaxation processes associated with: (I) the dipolar motions in the short oxyethylene side chains of P(EO/EM) (β); and (II) the segmental motion of the main chains comprising the polyether components (αfast, αslow). αslow is attributed to the slow α-relaxation of P(EO/EM) macromolecules, which is hindered by the strong coordination interactions with the ions. Two conduction processes are observed, σDC and σID, which are attributed, respectively, to the bulk conductivity and the interdomain conductivity. The temperature dependence of conductivity and relaxation processes reveals that αfast and αslow are strongly correlated with σDC and σID. The "in situ" BES measurements under pressurized CO2 indicate a fast decrease in σDC at the initial CO2 treatment time resulting from the decrease in the concentration of polyether-M(n+) complexes, which is driven by the CO2 permeation. The relaxation frequency (fR) of αslow at the initial CO2 treatment time increases and shows a steep rise with time with the same behavior of the αfast mode. It is demonstrated that the interactions between polyether chains of P(EO/EM) and cations in the polymer electrolyte layers embedded in Sa are probably weakened by the low permittivity of CO2 (ε = 1.08). Thus, the formation of ion pairs in the polymer electrolyte domains of P(EO/EM)-Sa occurs, with a corresponding reduction in the concentration of ion carriers.

Spectroscopic ellipsometry and UV–vis studies at room temperature of the novel organic–inorganic hybrid of salt Bis (4-acetylanilinium) tetrachlorocadmiate

“…In the last few years, organic-inorganic hybrid materials have drawn great attention as new generation of high performance materials by reason of their interesting physical and chemical properties obtained from the combination of organic and inorganic materials in single compound [1][2][3][4]. Several studies have reported the use of organic-inorganic hybrid materials in optoelectronic or optical applications.…”

A lipophilic ionic liquid based on formamidinium cations and TFSI: the electric response and the effect of CO2 on the conductivity mechanism

“…9 The gas was pre-dried over a type-A zeolite bed in order to exclude any traces of water from the CO 2 , which could give rise to proton conductivity in the materials. This measurement setup allowed the measurements to be performed on extremely moisture sensitive materials such as PEO-based polymer electrolytes in totally anhydrous conditions 7 . A manual screw pump allowed the cell pressure to be increased to pressures higher than the gas cylinder.…”

“…The second goal of the study is addressed by modulating the electric response of the IL, measured with broadband electrical spectroscopy (BES), through the partial pressure of CO 2 (P CO2 ). CO 2 , with a permittivity of ε r = 1.08, 7 acts as a seed of aggregation that enhances the lipophilic behaviour of alkyl chains in the cationic aggregates and easily modulate the nano-morphology of the IL and therefore its electric response and conductivity mechanism.…”

Effect of soft segment molecular weight on the glass transition, crystallinity, molecular mobility and segmental dynamics of poly(ethylene oxide) based poly(urethane–urea) copolymers

“…Thus, morphology dependent dynamic processes taking place in polymers, which are on multiple length scales and different time scales can be identi-ed in an effort to understand the structural states of these materials. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] To date, various polymeric materials have been, and continues to be, analyzed by DRS. [13][14][15][16][17][18][19][20] In polyurethanes, this technique is mainly used to investigate the local dynamics, dynamic glass transition and indirectly, crystallinity and microphase morphology.…”

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] To date, various polymeric materials have been, and continues to be, analyzed by DRS. [13][14][15][16][17][18][19][20] In polyurethanes, this technique is mainly used to investigate the local dynamics, dynamic glass transition and indirectly, crystallinity and microphase morphology. [21][22][23][24][25][26][27][28] Combination of DSC and DRS enables us to gain a complete understanding of the structural variables, such as so segment type and molecular weight and hard segment structure and content on the molecular mobility and segmental dynamics in polyurethanes.…”