Quantifying Single-Ion Transport in Percolated Ionic Aggregates of Polymer Melts

Bollinger, Jonathan A.; Stevens, Mark J.; Frischknecht, Amalie L.

doi:10.1021/acsmacrolett.0c00139

Cited by 23 publications

(68 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The low dielectric constants of polymers typically drive the aggregation of ions. As a consequence, the X-ray scattering of ionomers often exhibits a sharp peak at low wave vectors, which is commonly referred to as the “ionomer peak”. − The morphology of ionic aggregates has been studied extensively in both experiments − and simulations, − and excellent reviews on this topic have been recently provided by Winey and co-workers and Hall and co-workers . The profound impact of ionic aggregates on the dynamics of ionomers has been discussed in detail by Chen and co-workers .…”

Section: Introductionmentioning

confidence: 99%

Influence of Ionic Interaction Strength on Glass Formation of an Ion-Containing Polymer Melt

Yang

2021

Macromolecules

View full text Add to dashboard Cite

A deep understanding of the glass formation of ion-containing polymers is crucial for applications of high technological relevance, but it remains a significant challenge to develop a molecular theory to predict thermodynamic and dynamic properties of these materials. Here, we perform extensive molecular dynamics simulations of an ion-containing polymer melt having variable ionic interaction strength to address the essential phenomenology of thermodynamic and dynamic properties upon approaching the glass-transition temperature. Both thermodynamic and dynamic properties are shown to be strongly influenced by ionic interaction strength. The characteristic temperatures of glass formation increase with increasing ionic interaction strength in a nearly linear fashion, a trend that can be rationalized based on changes in the cohesive energy density induced by ionic interactions. The growth of fragility with increasing ionic interaction strength is found to be somewhat nonlinear. Moreover, we demonstrate that the string model of glass formation provides an excellent description of the relationship between the structural relaxation time and the string length in our ion-containing polymer melt having variable ionic interaction strength, implying that the entropy theory provides a promising tool for investigating the glass formation of ion-containing polymers if ionic interactions are incorporated properly. The string model also allows us to establish the general trends of the enthalpy and entropy of high temperature activation in variation with ionic interaction strength, fundamental energetic parameters that play a key role in the entropy theory of glass formation. Our simulation results should be helpful for developing a general framework to understand the glass formation of ion-containing polymers.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of Ionic Interaction Strength on Glass Formation of an Ion-Containing Polymer Melt

Yang

2021

Macromolecules

View full text Add to dashboard Cite

show abstract

“…18 Local ion transport in aggregated domains is postulated to be higher in some systems due to the close proximity of solvation sites. 12,16,17,22,23 In this case, the ionic mobility is related to the extent to which aggregates form continuous domains through the material. 12,[15][16][17] In contrast to ion conduction, electron transport in semicrystalline conjugated polymers is often related to the degree of long-range order in the polymer and the degree of ionization.…”

Section: Introductionmentioning

confidence: 99%

Li⁺ and Oxidant Addition To Control Ionic and Electronic Conduction in Ionic Liquid-Functionalized Conjugated Polymers

et al. 2021

View full text Add to dashboard Cite

Conduction of ions and charge (electrons) often follow distinct materials design rules, presenting a significant challenge for the development of homogeneous materials that are good at both. The fundamental interactions that dictate ionic and electronic conduction in mixed conductors are still unclear. Here, we characterize the ionic and electronic conduction of a class of mixed polymeric conductors in which ionic liquid groups are tethered to an electron conducting conjugated polymer backbone. A model conjugated polymeric ionic liquid, poly{3-[6'-(N-methylimidazolium)hexyl]thiophene}BF4 -(P3HT-IM), is synthesized and shown to have significant long range ordering. Chemical oxidation of the polymer results in a room temperature electronic conductivity of 10 -2 S cm -1 . The polymer is also capable of dissolving Li + salt up to a concentration of rsalt = 1 [moles of salt]/[moles of monomer]. The polymer displays a monotonic increase in ionic conductivity with salt concentration, reaching a maximum room temperature ionic conductivity of 10 -5 S cm -1 at the highest concentration of rsalt = 1. Notably, this is among the first studies to characterize both the ionic and electronic conductivity of an ionic liquid functionalized conjugated polymer upon the addition of oxidant and salt. All-atom molecular dynamics simulations indicate that the imidazolium side chains promote the formation of a percolated network of solvation sites at high salt concentrations, which facilitates ion transport. Pulsed-Field Gradient NMR diffusivity measurements and MD indicate a lithium transference number around 0.5, suggesting that the percolated solvation network promotes lithium transport in a way that is unique from many ion conducting systems. These results suggest that the addition of diffuse, ionic liquid-like groups to a conjugated polymer backbone serves as an effective design approach to facilitate simultaneous lithium-ion conduction and electronic conduction in the absence of solvent.

show abstract

“…This general prediction valid for large barriers is consistent with prior simulation and experimental results in the literature. 12,27,31 If the barrier is weak, the full expression given in eq 28 needs to be used in conjunction with eq 1 to obtain the τ-dependence of the ionic conductivity.…”

Section: ■ Author Informationmentioning

confidence: 99%

“…The subject of ionic conductivity in polymeric materials with heterogeneous structures is of intense current interest, primarily due to the societal need for better battery alternatives. − Significant progress has recently been made toward formulating polymeric materials with enhanced ionic conductivities and at the same time not compromising on their mechanical stability. The procedures that have been implemented in this endeavor are primarily experiments and simulations. − Generally speaking, the investigated systems include solid polymer electrolytes such as salt-doped poly(ethylene oxide), polymeric single-ion conductors, polymerized ionic liquids, and polyelectrolyte solutions in nanocapillaries. − …”

mentioning

confidence: 99%

Theory of Ionic Conductivity with Morphological Control in Polymers

Muthukumar

2021

ACS Macro Lett.

View full text Add to dashboard Cite

We present a general theory of ionic conductivity in polymeric materials consisting of percolated ionic pathways. Identifying two key length scales corresponding to interpath permeation distance ξ and one-dimensional hopping conduction path length mλ, we have derived closed-form formulas in terms of the energy U required to unbind a conductive ion from its bound state and the partition ratio ξ/mλ between the three-dimensional permeation and one-dimensional hopping pathways. The results provide design strategies to significantly enhance ionic conductivity in single-ion conductors. For large barriers to dissociate an ion, corrections to the Arrhenius law are presented. The predicted dependence of ionic conductivity on the unbinding time is in agreement with results in the literature based on simulations and experiments. This theory is generally applicable to conductive systems where the two mechanisms of permeation and hopping occur concurrently.

show abstract

Quantifying Single-Ion Transport in Percolated Ionic Aggregates of Polymer Melts

Cited by 23 publications

References 28 publications

Influence of Ionic Interaction Strength on Glass Formation of an Ion-Containing Polymer Melt

Influence of Ionic Interaction Strength on Glass Formation of an Ion-Containing Polymer Melt

Li⁺ and Oxidant Addition To Control Ionic and Electronic Conduction in Ionic Liquid-Functionalized Conjugated Polymers

Theory of Ionic Conductivity with Morphological Control in Polymers

Contact Info

Product

Resources

About

Quantifying Single-Ion Transport in Percolated Ionic Aggregates of Polymer Melts

Cited by 23 publications

References 28 publications

Influence of Ionic Interaction Strength on Glass Formation of an Ion-Containing Polymer Melt

Influence of Ionic Interaction Strength on Glass Formation of an Ion-Containing Polymer Melt

Li+ and Oxidant Addition To Control Ionic and Electronic Conduction in Ionic Liquid-Functionalized Conjugated Polymers

Theory of Ionic Conductivity with Morphological Control in Polymers

Contact Info

Product

Resources

About

Li⁺ and Oxidant Addition To Control Ionic and Electronic Conduction in Ionic Liquid-Functionalized Conjugated Polymers