Dynamics of Sulfonated Polystyrene Ionomers Using Broadband Dielectric Spectroscopy

Abstract

The dynamics of sulfonated polystyrene ionomers were investigated by using broadband dielectric relaxation spectroscopy. Dynamic mechanical analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and small-angle X-ray scattering were employed in a complementary role. Sulfonated polystyrene ionomers were prepared from the precursor sulfonic acid polystyrene, having 1 and 7 mol % sulfonic acid, by exchanging the protons of the acid functionality with Na, Cs, and Zn cations. Three dielectric relaxations were observed above the glass transition temperature: the segmental R process and relaxations associated with Maxwell-Wagner-Sillars interfacial polarization and electrode polarization. The low-frequency broadening of the R transition is related to constraints imposed by the ionic aggregates. A relaxation in the glassy state was observed for the precursor sulfonic acid polystyrene and ionomers and attributed to the local motion of sulfonated phenyl groups. The relaxation strengths of the β processes of the ionomers were suppressed by interaction with the cations that create physical cross-links, and the relaxation times decreased with increasing strength of the electrostatic interaction of the ion pairs.

Polymer chain dynamics in epoxy based composites as investigated by broadband dielectric spectroscopy

“…However, the dominant feature is one that extends from low f into higher frequencies. The slight downward curvature of the graphs in proceeding to low f is tentatively assumed to be due to a superposition of high frequency wings of off-scale peaks arising from sample-electrode interfacial polarization relaxation (Klein et al, 2006;Chen et al, 2011;Atorngitjawat and Runt, 2007). This suggestion is supported by corresponding high e 0 values at low f (figure not shown).…”

“…Also, there is no signature of sample-electrode interfacial polarization relaxation on the loss spectra (i.e., downturn from high e 00 values in proceeding to the lowest frequencies) (Klein et al, 2006;Chen et al, 2011;Atorngitjawat and Runt, 2007).…”

Ion Conduction and Polymer Dynamics of Poly(2-vinylpyridine)-Lithium Perchlorate Mixtures

“…38 We have used this approach previously in the investigation of the dipolar relaxation behavior of sulfonated polystyrene ionomers. 39 Relaxation times, τ max () 1/2πf max ), and dielectric relaxation strengths, ∆ , were obtained by fitting the isothermal dielectric loss ′′(f) and ′′ KK (f) curves for data measured below T g and above T g , respectively, with the Havriliak-Negami (HN) function. The sum of multiple HN functions and a dc loss contribution were used to fit the experimental loss curves 40 where *, ′, and ′′ are the complex, real, and imaginary components of the dielectric permittivity, respectively.…”

“…54 Finally, the highest temperature process, R 4 , is clearly due to electrode polarization, as indicated by the high values of ′′ and strong concurrent increases in ′ ( Figure 11). 39,49 The relaxation times of the R 1 processes follow the Vogel-Fulcher-Tammann (VFT) relation, τ max ) τ 0 exp[B/(T -T 0 )], 55 as shown by the fits in Figure 10, and fitting parameters are provided in Table 1. 3.5. Conductivity.…”

Structure and Dynamics of Zinc-Neutralized Sulfonated Polystyrene Ionomers

“…Dielectric relaxation spectroscopy has been used to investigate the dynamics of some ionomers, predominantly on poly(styrene-co-methacrylic acid) and poly(ethyleneco-methacrylic acid) ionomers, 1,14,15 but very little has been done on sulfonated polystyrene. 16,17 We intend to elucidate the connection between aggregate morphology and dynamics by applying an integrated and systematic approach using sulfonated polystyrene (SPS) as a model ionomer.In our previous paper, we demonstrated that sulfonation has an important effect on the structure and dynamics of sulfonated polystyrene acid copolymers (having 3.5, 6.7, and 9.5 mol % sulfonation), the precursors to the ionomers investigated herein. 18 In this publication we will focus on the effect of neutralizing these materials with zinc.…”