Polymer Chain Mobility under Shear—A Rheo-NMR Investigation

Wiesner, Brigitte; Kohn, Benjamin; Mende, Mandy; Scheler, Ulrich

doi:10.3390/polym10111231

Cited by 8 publications

(4 citation statements)

References 16 publications

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“…Strong dipolar coupling in rigid samples induces faster decoherence, while in samples with high molecular mobility, T 2 can be longer as the process is less efficient. In polymeric systems, greater entanglements and/or cross-linking density results in a decrease in mobility that manifests as shorter T 2 values. , In Figure , we illustrate the T 2 values collected for these 12 samples as a function of RH and CO 2 exposure.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Fundamental Insight into Humid CO₂ Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

et al. 2023

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Direct air capture (DAC) technology is being explored as a pathway for reducing greenhouse gas emissions through the efficient removal of CO2 from the atmosphere. However, there remains a knowledge gap regarding structure–property–performance factors that impact the behavior of these systems in diverse, real-world environments. In aminopolymer-based DAC systems, gas diffusion is tightly coupled with polymer mobility, which is in turn affected by a large matrix of variables, including interactions with the pore wall of the support, nanoconfinement, the presence of co-adsorbates (moisture), and electrostatic cross-links that develop as a function of CO2 chemisorption. Higher-throughput, benchtop techniques for studying and understanding mobility in these systems would lead to more rapid advances in the field. Here, we demonstrate the value of a fluorescence technique for monitoring polymer mobility within nanocomposite capture materials as a function of CO2 and water adsorption in a series of humidified polyethylenimine-Al2O3 composite materials. The approach allows us to correlate changes in mobility with CO2 adsorption kinetics as a function of relative humidity. We further couple this information with NMR relaxometry data attained using a portable single-sided magnetic resonance device, and we employ diffuse reflectance infrared Fourier transform spectroscopy to correlate the formation of different relative amounts of carbamates and carbonates with the environmental conditions. These results provide a blueprint for using benchtop techniques to promote fundamental understanding in DAC systems that can in turn enable more efficient operation in real-world conditions.

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Section: Resultsmentioning

confidence: 99%

“…In polymeric systems, greater entanglements and/or cross-linking density results in a decrease in mobility that manifests as shorter T 2 values. 65,66 In Figure 4, we illustrate the T 2 values collected for these 12 samples as a function of RH and CO 2 exposure.…”

Section: Methodsmentioning

confidence: 99%

Fundamental Insight into Humid CO₂ Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

et al. 2023

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“…Concurrent steady or dynamic rheological measurements and time-domain NMR spectroscopy can provide information about the relationship between the polymer mobility, orientation, or crystallization and sample deformation or mechanical properties. For example, shear induced changes in entanglement dynamics, shear history effects on crystallization, and polymer–inorganic filler interactions and their effect on crystallization have all been characterized through rheo-NMR techniques. − Rheo-NMR has many potential applications in the study of reversible gels to understand the coupling between macroscopic mechanical deformation and molecular cross-linking and dynamics. For example, rheo-NMR has shown that shear reduces the intermolecular linkages between κ-carrageenan, a seaweed extract that undergoes thermoreversible gelation in solution and is used as a polysaccharide thickener in the food industry …”

Section: Network Mechanics and Dynamicsmentioning

confidence: 99%

Molecular Characterization of Polymer Networks

et al. 2021

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Polymer networks are complex systems consisting of molecular components. Whereas the properties of the individual components are typically well understood by most chemists, translating that chemical insight into polymer networks themselves is limited by the statistical and poorly defined nature of network structures. As a result, it is challenging, if not currently impossible, to extrapolate from the molecular behavior of components to the full range of performance and properties of the entire polymer network. Polymer networks therefore present an unrealized, important, and interdisciplinary opportunity to exert molecular-level, chemical control on material macroscopic properties. A barrier to sophisticated molecular approaches to polymer networks is that the techniques for characterizing the molecular structure of networks are often unfamiliar to many scientists. Here, we present a critical overview of the current characterization techniques available to understand the relation between the molecular properties and the resulting performance and behavior of polymer networks, in the absence of added fillers. We highlight the methods available to characterize the chemistry and molecular-level properties of individual polymer strands and junctions, the gelation process by which strands form networks, the structure of the resulting network, and the dynamics and mechanics of the final material. The purpose is not to serve as a detailed manual for conducting these measurements but rather to unify the underlying principles, point out remaining challenges, and provide a concise overview by which chemists can plan characterization strategies that suit their research objectives. Because polymer networks cannot often be sufficiently characterized with a single method, strategic combinations of multiple techniques are typically required for their molecular characterization.

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“…In polymeric systems, greater entanglements and/or crosslinking density results in a decrease in mobility that manifests as shorter T 2 values. 62,63 In Figure 5, we illustrate the T 2 values collected for these twelve samples as a function of RH and CO 2 exposure. Performing an inverse Laplace transform on the T 2 echo train decay curves produces relaxation spectra (plotted in Fig.…”

Section: Nmr Mobile Universal Surface Explorer (Mouse)mentioning

confidence: 99%

Fundamental Insight into Humid CO2 Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

Russell-Parks

Leick

Marple

et al. 2023

Preprint

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Direct air capture (DAC) technology is being explored as a pathway for reducing greenhouse gas emissions through the efficient removal of CO2 from the atmosphere. However, there remains a knowledge gap regarding structure-property-performance factors that impact the behavior of these systems in diverse, real-world environments. In aminopolymer-based DAC systems, gas diffusion is tightly coupled with polymer mobility, which is in turn affected by a large matrix of variables, including interactions with the pore wall of the support, nanoconfinement, the presence of co-adsorbates (moisture), and electrostatic crosslinks that develop as a function of CO2 chemisorption. Higher throughput, benchtop techniques for studying and understanding mobility in these systems would lead to more rapid advances in the field. Here, we demonstrate the value of a fluorescence technique for monitoring polymer mobility within nanocomposite capture materials as a function of CO2 and water adsorption in a series of humidified polyethylenimine-Al2O3 composite materials. The approach allows us to correlate changes in mobility with CO2 adsorption kinetics as a function of relative humidity. We further couple this information with NMR relaxometry data attained using a portable single-sided magnetic resonance device, and we employ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to correlate the formation of different relative amounts of carbamates and carbonates with the environmental conditions. These results provide a blueprint for using benchtop techniques to promote fundamental understanding in DAC systems that can in turn enable more efficient operation in real-world conditions.

show abstract

Polymer Chain Mobility under Shear—A Rheo-NMR Investigation

Cited by 8 publications

References 16 publications

Fundamental Insight into Humid CO₂ Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

Fundamental Insight into Humid CO₂ Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

Molecular Characterization of Polymer Networks

Fundamental Insight into Humid CO2 Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

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