Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution00:52

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

1.2K
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
1.2K
Polymers: Molecular Weight Distribution01:10

Polymers: Molecular Weight Distribution

4.5K
For any given polymer, the weight average molecular weight (Mw) is higher than, if not equal to, the number average molecular weight (Mn). The only situation in which the weight average molecular weight and the number average molecular weight are equal is when a polymer consists only of chains with equal molecular weight. However, this never happens in a synthetic polymer, since it is difficult to control the polymerization process up to a molecular level with accuracy to a hundred percent.
4.5K
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR01:15

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

1.6K
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
1.6K
Molecular Weight of Step-Growth Polymers01:08

Molecular Weight of Step-Growth Polymers

2.7K
Step growth polymerization involves bi or multifunctional monomers. Bifunctional monomers react to form linear step growth polymers, whereas multifunctional monomers react to form non-linear or branched polymers.
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
2.7K
¹H NMR: Complex Splitting01:13

¹H NMR: Complex Splitting

1.7K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.7K
Polymer Classification: Architecture01:14

Polymer Classification: Architecture

3.6K
Polymers are classified as linear or branched on the basis of their chain architecture. The polymer chains in linear polymers have a long chain-like structure with minimal to no branching at all. Even if a polymer features large substituent groups on the monomer, which appear as branches to the skeleton, it is not considered a branched polymer. A branched polymer contains secondary polymer chains that arise from the main polymer chain. The branching occurs when the polymer growth shifts from...
3.6K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Mocetinostat Ameliorates Pathological Cardiac Hypertrophy via Suppression of Ferroptosis Through Nrf2 Pathway.

Die Pharmazie·2026
Same author

Antibiotic-mediated gut microbiota depletion partially attenuates methamphetamine-induced reward and linoleic acid metabolic disturbance.

Neuropharmacology·2026
Same author

SQ-KFP: A Framework for Spatially Quantitative Metabolic Flux Analysis Enables Imaging the <i>In Vivo</i> Absolute Metabolic Enzymatic Reaction Rate.

Analytical chemistry·2026
Same author

Rotational memory function of SPC/E water.

The Journal of chemical physics·2026
Same author

Semaglutide ameliorates aortic endothelial cell dysfunction in sarcopenia through the SIRT1/cGAS-STING signaling axis.

Free radical biology & medicine·2026
Same author

4-Octyl itaconate against septic cardiac injury by suppressing cardiac lymphatic vessel inflammation via the RhoA-ROCK1 signaling pathway.

Clinical science (London, England : 1979)·2026

Related Experiment Video

Updated: Dec 22, 2025

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
06:55

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Published on: September 26, 2016

8.3K

Elucidating the 1H NMR Relaxation Mechanism in Polydisperse Polymers and Bitumen Using Measurements, MD Simulations,

Philip M Singer1, Arjun Valiya Parambathu1, Xinglin Wang1

  • 1Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States.

The Journal of Physical Chemistry. B
|May 2, 2020
PubMed
Summary

This study explains the frequency dependence of 1H NMR T1 relaxation and viscosity dependence of T2 in polymers and bitumen. A new phenomenological model and molecular dynamics simulations clarify these complex NMR relaxation behaviors.

More Related Videos

Author Spotlight: Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
06:54

Author Spotlight: Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems

Published on: June 23, 2023

1.2K
MALDI-ToF MS Method for the Characterization of Synthetic Polymers with Varying Dispersity and End Groups
06:16

MALDI-ToF MS Method for the Characterization of Synthetic Polymers with Varying Dispersity and End Groups

Published on: October 3, 2025

1.2K

Related Experiment Videos

Last Updated: Dec 22, 2025

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
06:55

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Published on: September 26, 2016

8.3K
Author Spotlight: Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
06:54

Author Spotlight: Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems

Published on: June 23, 2023

1.2K
MALDI-ToF MS Method for the Characterization of Synthetic Polymers with Varying Dispersity and End Groups
06:16

MALDI-ToF MS Method for the Characterization of Synthetic Polymers with Varying Dispersity and End Groups

Published on: October 3, 2025

1.2K

Area of Science:

  • Physical Chemistry
  • Polymer Science
  • Materials Science

Background:

  • The frequency dependence of 1H nuclear magnetic resonance (NMR) T1 relaxation and the viscosity dependence of T2 in polydisperse polymers and bitumen are not well understood.
  • Existing models fail to fully explain the observed anomalous behaviors in these complex systems.

Purpose of the Study:

  • To elucidate the underlying mechanisms of 1H NMR relaxation in polydisperse polymers and bitumen.
  • To develop and validate a model that accounts for the frequency and viscosity dependencies of T1 and T2.

Main Methods:

  • NMR relaxation measurements (T1, T2, field-cycling T1, T1ρ) across a wide range of frequencies and viscosities.
  • Development of a phenomenological model incorporating a distribution of correlation times and internal polymer dynamics.
  • Molecular dynamics (MD) simulations to complement experimental findings.

Main Results:

  • A phenomenological model successfully explains the anomalous log-mean relaxation times (T1LM ∝ f0 and T2LM ∝ (η/T)-1/2) in polymers and bitumen.
  • MD simulations show good agreement with experimental measurements and the proposed model for polymer systems.
  • The study suggests a common NMR relaxation mechanism for viscous polydisperse fluids and fluids under nanoconfinement.

Conclusions:

  • The developed phenomenological model provides a unified explanation for complex NMR relaxation phenomena in polydisperse polymers and bitumen.
  • Molecular dynamics simulations validate the model and experimental observations.
  • The findings indicate a shared NMR relaxation mechanism across different complex fluid environments, challenging previous assumptions.