Synthesis, characterization, and ionic conductivity of nanocomposites: Polyelectrolyte systems

Macromolecular Symposia

Vázquez

García

et al. 2013

Summary: Polymeric electrolyte composites based on polymer poly(sulfobutylbetaines) (PMBS-4) and 1%, 3% and 5% montmorillonite (MMT) modified with organic ions, dodecyldimethyl(3-sulfo-propyl) ammonium hydroxide (C 12 SB) were synthesized. The structural modification and electrochemical properties of samples were investigated to understand the effects of organic MMT in a polymer matrix on ionic conductivity. The modification of the clay with organic ions resulted in a larger d-spacing which makes easier the penetration of PMBS-4 into the interlayer galleries. The values of T g obtained from differential scanning calorimetry are 18 8C, 20 8C, 20 8C and 27 8C for PMBS-4, PMBS-4/C 12 SB-MMT 1%, PMBS-4/C 12 SB-MMT 3% and PMBS-4/C 12 SB-MMT 5% respectively. Since PMBS-4 and PMBS/C 12 SB-MMT were examined in the absence of Li salt, the conductivity of samples was attributed to the motion of dipoles in chains of zwitterionic PMBS-4. The increase in conductivity with increasing temperature was explained as a local structural relaxation and segmental motion of polymer. The values of s, at 25 8C, for: PMBS-4, PMBS-4/C 12 SB-MMT 1%, PMBS-4/C 12 SB-MMT 3% and PMBS-4/C 12 SB-MMT 5% were 6.2 Â 10 À6 S/cm, 1.2 Â 10 À6 S/cm, 1.7 Â 10 À6 S/cm and 9.1 Â 10 À6 S/cm respectively.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphology, Dielectric and Thermal Properties of Poly(sulfobutylbetaine)/Montmorillonite (PMBS‐4/MMT) Nanocomposites as Solid Polymer Electrolytes

Macromolecular Symposia

Vázquez

García

et al. 2013

“…14 DMAEMA was purified by vacuum distillation (84 C/15 mmHg). 14 DMAEMA was purified by vacuum distillation (84 C/15 mmHg).…”

Section: Polymer Synthesismentioning

confidence: 99%

“…14 The results suggested that the dielectric properties were a function of morphology and prompted us to further investigate the influence of nanostructure on the thermal and viscoelastic properties of these materials. The PDMAEM matrix, its protonated polymer (PDMAEMH), and the nanocomposites based on PDMAEMH/MMT (PH/clay) have been studied using dielectric spectroscopy and by high resolution transmission electron microscopy (HRTEM) demonstrating exfoliation and intercalation morphologies as a function of the type of surfactant used.…”

Section: Introductionmentioning

confidence: 99%

Nanostructure and viscoelasticity of layered silicate nanocomposite–electrolyte supports

J of Applied Polymer Sci

Romo-Uribe

Flores

2011

There is the need for novel polyelectrolytes with enhanced thermal and mechanical properties. In this report, we have reinforced a polyelectrolyte based on poly(dimethylaminoethylmethacrylate) (PDMAEM) using nanoclay montmorillonite (MMT), and have studied the thermal and viscoelastic properties. The protonated polymer (PDMAEMH) was solution mixed with functionalized MMT. Recognizing that the sort of surfactant may have a profound influence on the physical properties of the polymer matrix, neat MMT, and MMT treated with different surfactants (sulfobetaine and ammonia) were used, and the concentration of the nanofiller was varied from 1 to 5%w/ w. Strikingly, while PDMAEM exhibited a glass transition temperature T g of 32 C, the protonated PDMAEMH showed T g ¼ 155 C. Master curves obtained by applying the time-temperature superposition principle showed that PDMAEM behaved predominantly elastic (G 00 < G 0 ) sug-gesting an entangled polymer melt. However, PDMAEMH exhibited much longer relaxation times, a shift of ca. seven decades in frequency, suggesting that ionic interactions significantly hampered the molecular dynamics. X-ray scattering demonstrated that lower concentration and sulfobetaine surfactant favored exfoliation whereas ammonia and untreated MMT favored intercalation of the nanoplates. Furthermore, an enhancement in dynamic storage shear modulus was observed for the nanocomposites exhibiting intercalated morphologies relative to those displaying an exfoliated morphology. It is then suggested that the molecular dynamics is further slowed down due to confinement of the macromolecules between the nanoplates. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 944-955, 2012

“…Due to the current availability of nanoparticles with well‐defined size and morphology different states of confinement can be achieved for polymer nanocomposites: (i) polymer chains constrained by nanoclay, (ii) polymer chains inside nanopores or nanocylinders, or (iii) inorganic nanoparticles and hybrids (i.e., silica, alumina, POSS, and so on) dispersed in a polymer matrix …”

Section: Introductionmentioning

confidence: 99%

Viscoelasticity and Dynamics of Confined Polyelectrolyte/Layered Silicate Nanocomposites: The Influence of Intercalation and Exfoliation

Romo-Uribe

Macro Chemistry & Physics

2017

The influence of different confinement regimes on the linear viscoelastic properties of a polyelectrolyte, the protonated poly‐[(dimethylamino) ethyl methacrylate] (PDMAEMAH), is investigated. PDMAEMAH is reinforced with the layered silicate montmorillonite (MMT). Neat MMT and MMT treated with sulfobetaine and ammonia‐based surfactants (MMT/SB and MMT/NH, respectively) are utilized. Transmission electron microscopy and X‐ray scattering show that MMT and MMT/NH produce intercalated morphology, whereas MMT/SB produces an exfoliated morphology. Thus, the polyelectrolyte is under different confinement regimes. The confinement produces the increase of glass transition temperature Tg; however, the increase is larger for the (highly confined) intercalated morphology. Master curves are constructed applying time–temperature superposition. Strikingly, the viscoelastic spectra evidence that the intercalated morphology produces twofold increase of rubber‐like modulus, whereas the exfoliated morphology produces over fourfold reduction of rubber‐like modulus, both at 3 wt% clay concentration. The reduction of rubber‐like modulus suggests that an exfoliated morphology produces disruption of the entanglement density. Analysis in the segmental relaxation regime shows that the intercalated morphology induces longer relaxation times, that is, more dynamics retardation, in correlation with the increase of glass transition temperature. This research paves the road for better understanding of viscoelastic behavior and dynamics of molten polyelectrolytes under confinement.