Using Coupling Motion of Connecting Ions in Designing Telechelic Ionomers

Liu, Shuang; Sheng, Wu; Chen, Quan

doi:10.1021/acsmacrolett.0c00256

Cited by 12 publications

(11 citation statements)

References 48 publications

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“…In Figure 1, we find that the scattering profiles of the copolymer precursors (at the bottom of each panel) are characterized by two peaks. This feature is seen also for pure PS or P2VP in literature (Wu et al, 2019;Liu et al, 2020;Yu et al, 2021), where the high-and lowq peaks were attributable to the amorphous scattering of the 2VP and/or S moieties and the correlation of the main backbones, respectively. Introducing H 3 [P(W 3 O 10 ) 4 ] into the copolymer and pure P2VP leads to an additional peak appearing at the lower q.…”

Section: Structuresupporting

confidence: 62%

Morphology and rheology of composites of poly(styrene-co-2-vinyl pyridine) copolymers and phosphotungstic acid

Zhang²,

Zhang³

et al. 2022

Front. Soft. Matter

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Morphological and rheological properties are examined for poly(styrene-co-2-vinyl pyridine) (P(S-co-2VP)) copolymers upon introducing phosphotungstic acid, one kind of polyoxometalates (POMs). The phosphotungstic acid protonates the 2VP monomers, and the deprotonated phosphotungstic acid effectively crosslinks the protonated 2VP monomers, inducing phase segregation into the S-rich and 2VP-rich domains. Linear viscoelasticity (LVE) of the composite samples strongly relies on the continuity of the 2VP-rich domains and can be classified into the following three types. (1) For 2VP-rich sphere domains in the S-rich matrix, LVE is akin to the conventional elastomer characterized by a wide rubbery regime before the terminal relaxation. (2) For bicontinuous morphology, where both the 2VP-rich and S-rich domains are continuous, two glassy processes manifest in LVE, and the chain relaxation is controlled by the continuous ion dissociation in the less mobilized 2VP-rich domain. (3) When the 2VP-rich domain is the only continuous phase, only the glassy modulus of the 2VP-rich domain manifests in LVE, and the chain relaxation is activated by the continuous ionic dissociations in the matrix. Surprisingly, the relaxation time obtained for all three abovementioned morphologies can be reduced to a universal behavior once the average glass transition temperature of the 2VP-rich region and the number of effective stickers per chain have been properly normalized, indicating that these two parameters control the chain-dimensional dynamics.

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Section: Structuresupporting

confidence: 62%

Morphology and rheology of composites of poly(styrene-co-2-vinyl pyridine) copolymers and phosphotungstic acid

Zhang²,

Zhang³

et al. 2022

Front. Soft. Matter

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“…Recently, Chen et al tested this idea using two model systems: (1) The random ionomers at high ion content ∼1 ion per Kuhn segment 136 and (2) the telechelic ionomers with the number of connecting ions per chain end ranging from 0 to 3. 59 For the random ionomers, i.e., the high ion content SPS with cesium (Cs) as counterion, Chen et al observed from LVE (in Figure 4) that the glassy and rubbery moduli merged into one broad relaxation process upon increasing the ion content to ∼1 ion per Kuhn segment. (The large-size Cs counterion was chosen to lower the association energy of ionic interaction, thereby enabling LVE to be detectable without sample degradation at the high ion contents.)…”

Section: Theoretical Advances and Experimental Model Systemsmentioning

confidence: 99%

“…To synthesize these ionomers, Chen and co-workers first synthesized a poly-(isobutyl acrylate) (PiBA) precursor using a bifunctional RAFT agent (PiBA with low T g = −31 °C was chosen to extend the T range of the LVE measurements) and then polymerized a few ionic groups at the two ends. 59 Unlike the conventional telechelic ionomers having strictly one ion per chain end, 142−144…”

Section: Theoretical Advances and Experimental Model Systemsmentioning

confidence: 99%

Advances and New Opportunities in the Rheology of Physically and Chemically Reversible Polymers

Sheng

Chen

2021

Macromolecules

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The advances in understanding the dynamics of both the physically and chemically reversible networks are summarized from a rheological perspective. The focus is placed on linear viscoelasticity, which is related to thermodynamics and reversible kinetics at quasi-equilibrium states. We first explain basic assumptions and predictions of the reversible-network theories, including the reversible gelation, sticky-Rouse, and sticky-reptation theories. We then summarize the dynamic features of the state-of-the-art materials that have not been fully incorporated into the current theoretical framework: (1) cooperative motion of the nearby stickers significantly increases the dissociation energy of physically reversible networks, (2) the degree of gelation becomes highly T-dependent when the Gibbs free energy approaches the thermal energy for both the physically and chemically reversible networks, and (3) the exchange rate of dynamic cross-links of chemically reversible networks is reaction-controlled and depends on the chemical species and concentrations of the reactants. Finally, some pathways for future theoretical development are suggested.

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“…Ionomers usually contain a small number of ionic groups, often referred to as stickers, covalently attached to the polymer backbone. The stickers aggregate to form physical cross-links that improve the mechanical properties and add functionality to the base polymer, − which makes them suitable for a variety of applications, including membranes, compatibilizers, shape memory, and self-healing . Neat ionomers, however, usually exhibit low stretchability when rapidly deformed due to strain-induced dissociation of the ionic groups, and as a result, they often exhibit brittle, macroscopic fractures. − The macroscopic ductility of the associative polymer materials generally relies on the following: (1) microscopic stretchability of the stress-bearing network strands and (2) energy dissipation and structural rearrangements of the stickers when strain-induced breakup occurs. − …”

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confidence: 99%

Brittle-to-Ductile Transition of Sulfonated Polystyrene Ionomers

et al. 2021

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This study examines the brittle-to-ductile transition of sulfonated polystyrene ionomers (SPS) with different counterions. The polystyrene precursor was unentangled and had two ionic groups per chain on average. Thus, its terminal relaxation time was comparable to the lifetime of the associating ionic groups. Three types of ionomer samples were used to tune the association lifetime: (1) fully neutralized SPS with different alkali-metal counterions, (2) fully neutralized SPS with mixed sodium and cesium counterions, and (3) partially neutralized SPS with sodium or cesium counterions. For all three systems, the brittle-to-ductile transition could be represented by a diagram of two Weissenberg numbers, Wi and Wi R, defined with respect to the terminal and Rouse relaxation times, respectively. A flowable region existed at sufficiently low Wi, independent of Wi R. At higher Wi, a brittle-to-ductile transition of the ionomer melt occurred above a critical value of Wi R. To achieve ductility during the application of rapid elongational flow, the Rouse-type motions should be sufficiently slow relative to the rate of ion-dissociation, so that the strain-induced breakup of the ionic cross-links would not cause very strong chain retraction that may further lead to the macroscopic fracture.

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Using Coupling Motion of Connecting Ions in Designing Telechelic Ionomers

Cited by 12 publications

References 48 publications

Morphology and rheology of composites of poly(styrene-co-2-vinyl pyridine) copolymers and phosphotungstic acid

Morphology and rheology of composites of poly(styrene-co-2-vinyl pyridine) copolymers and phosphotungstic acid

Advances and New Opportunities in the Rheology of Physically and Chemically Reversible Polymers

Brittle-to-Ductile Transition of Sulfonated Polystyrene Ionomers

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