Effects of cyclic and acyclic amidine side-chains on the properties of polysiloxane ionomers constructed <i>in situ</i> from three uncharged components

Poon, Louis; Hum, Jacob R; Weiss, Richard G.

doi:10.1039/d2sm00382a

Cited by 2 publications

(3 citation statements)

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“…The amidine copolymers ( 1a , 1b , and 1c ) and amidinium ionomers ( 1a-6 , 1a-18 , 1b-6 , 1b-18 , 1c-6 , and 1c-18 ) were synthesized and characterized by published procedures and protocols, as were the imidazoline copolymer ( 2 ) and imidazolinium ionomers ( 2 - 6 and 2 - 18 ) . Molecular weight ranges for the copolymers were calculated using Barry’s relationship and the cst viscosities.…”

Section: Methodsmentioning

confidence: 99%

“…Previously, we reported on structure−property relationships of neat ionomers comprised of polydimethylsiloxanes with amidine or imidazole side chains and alkyldithiocarbamic acid complexing agents. 10,12 Whereas the ionomers with octadecyldithiocarbamates contained amorphous regions, as well as crystalline domains generated by van der Waals interactions, those with the hexyldithiocarbamates were amorphous viscous liquids. Although the mechanisms for ion transport in both types of these ionomers are very interesting, we have focused here on experiments with the completely amorphous ones, reasoning that results from them will be more amenable to identifying the factors responsible for the ion transport and its temperature dependence.…”

Section: Ionic Conductivity and Zero-shear Viscosity Of Neat Ionomers...mentioning

confidence: 99%

“…Polydimethylsiloxane copolymer designations and their molecular weight ranges (from the supplier, Gelest) are collected in Table 1 for the amidine copolymers: poly [ The amidine copolymers (1a, 1b, and 1c) and amidinium ionomers (1a-6, 1a-18, 1b-6, 1b-18, 1c-6, and 1c-18) were synthesized and characterized by published procedures and protocols, 10 as were the imidazoline copolymer (2) and imidazolinium ionomers (2-6 and 2-18). 12 Molecular weight ranges for the copolymers were calculated using Barry's relationship 13 and the cst viscosities.…”

Section: ■ Introductionmentioning

confidence: 99%

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Ion-Transport Properties of Polydimethylsiloxane-Based Ionomers with Amidinium or Imidazolinium Alkyldithiocarbamate Pendant Groups in Low Dielectric Solvents or as Neat Liquids

2022

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The ion transport properties of ionomers comprised of polydimethylsiloxanes with amidinium or imidazolinium attached side chains and alkyldithiocarbamate anions (where alkyl is hexyl or octadecyl) have been investigated in chloroform solutions principally and as neat liquids. The influence of modifying the molecular weights of the polydimethylsiloxanes, the frequency of their amidininium or imidazolinium side groups, and temperature on the conductivity have been explored. When a solvent more polar than chloroform, syn-tetrachloroethane, was employed, a large increase in the ionic conductivity was found despite there being an increase in the viscosity of the solution. At least in these two solvents, polarity is more important in determining the conductivity than the viscosity. When normalized for ion content, Walden plots of the ionomer solutions at different ionomer concentrations approached values found for 1 M aqueous KCl. As neat liquids, the amidinium and imidazolinium hexyldithiocarbamate ionomers exceeded the values associated with the “superionic” region of the Walden plot (i.e., above the conductivity values for 1 M aqueous KCl). As ion content and polymer molecular weight increased, larger decoupling between bulk viscosity and ionic conductivity was noted, probably as a result of changes in the dynamic fragility of the ionomers.

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Section: Methodsmentioning

confidence: 99%

Section: Ionic Conductivity and Zero-shear Viscosity Of Neat Ionomers...mentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Ion-Transport Properties of Polydimethylsiloxane-Based Ionomers with Amidinium or Imidazolinium Alkyldithiocarbamate Pendant Groups in Low Dielectric Solvents or as Neat Liquids

2022

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Elastomers mechanically reinforced and toughened with CO2 gas

Miwa,

Yoneda,

Ohya

et al. 2024

Commun Mater

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Gas-responsive polymers have recently attracted considerable interest as unconventional smart materials that provide a new path toward the utilization of specific gases including CO2. Herein, we report gas-responsive elastomers that enhance mechanical properties, such as modulus, strength, stretchability, and toughness with CO2 gas. Various types of amine groups are introduced into polydimethylsiloxane elastomers to achieve the gas-induced mechanical reinforcement. In these elastomers, the amines form ionic crosslinks with CO2 gas that mechanically strengthen the materials. Furthermore, nanodomains formed via microphase separation of the ionic components behave similarly to viscoelastic nanofillers that dissipate a large amount of energy during deformation, thereby remarkably toughening the elastomers. Surprisingly, the fracture energy of the elastomer with diamine increases ~35 times in CO2 gas compared with that in N2 gas. Furthermore, the elastomers sensitively respond even to CO2 gas concentrations as low as 10 % and are remarkably toughened. Our design concept is widely applicable to the CO2 reinforcement of other polymers, such as polyethylene.

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Effects of cyclic and acyclic amidine side-chains on the properties of polysiloxane ionomers constructed in situ from three uncharged components

Abstract: Small structural changes to side chain groups have large consequences to the structures and dynamics of corresponding polysiloxane-based ionomers.

Cited by 2 publications

References 39 publications

Ion-Transport Properties of Polydimethylsiloxane-Based Ionomers with Amidinium or Imidazolinium Alkyldithiocarbamate Pendant Groups in Low Dielectric Solvents or as Neat Liquids

Ion-Transport Properties of Polydimethylsiloxane-Based Ionomers with Amidinium or Imidazolinium Alkyldithiocarbamate Pendant Groups in Low Dielectric Solvents or as Neat Liquids

Elastomers mechanically reinforced and toughened with CO2 gas

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