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

Polymers: Molecular Weight Distribution01:10

Polymers: Molecular Weight Distribution

3.2K
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.
3.2K
Molecular Weight of Step-Growth Polymers01:08

Molecular Weight of Step-Growth Polymers

2.1K
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...
2.1K
Polymers: Defining Molecular Weight01:01

Polymers: Defining Molecular Weight

2.7K
Unlike small molecules with definite molecular weights, polymers are a mixture of individual polymer chains of varying lengths, each with a unique molecular weight.  So, the molecular weight of a polymer is expressed as an average value based on the average size of the polymer chains. The two most common forms of averages used for polymers are the number average molecular weight and weight average molecular weight.
The number average molecular weight (Mn) is the summation of the number...
2.7K
¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

932
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
932
High-Resolution Mass Spectrometry (HRMS)01:15

High-Resolution Mass Spectrometry (HRMS)

1.1K
The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For...
1.1K
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution00:52

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

784
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...
784

You might also read

Related Articles

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

Sort by
Same author

Active-site recognition enables hydroxylation of a fluorine-deactivated C-H bond in 6,6,6-trifluoro-L-norleucine.

Chemical communications (Cambridge, England)·2026
Same author

Improved 2PP additive manufacturing build/process quality <i>via</i> the use of hyperbranched pre-polymer.

Faraday discussions·2025
Same author

Microscopic crystallographic analysis of dislocations in molecular crystals.

Nature materials·2025
Same author

Photophysical, thermal and imaging studies on vancomycin functional branched poly(<i>N</i>-isopropyl acrylamide) of differing degrees of branching containing nile red for detection of Gram-positive bacteria.

Journal of materials chemistry. B·2024
Same author

Volumetric printing and non-destructive drug quantification of water-soluble supramolecular hydrogels.

Drug delivery and translational research·2024
Same author

Real-Time Determination of Molecular Weight: Use of MaDDOSY (Mass Determination Diffusion Ordered Spectroscopy) to Monitor the Progress of Polymerization Reactions.

ACS polymers Au·2024

Related Experiment Video

Updated: May 15, 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

7.8K

Overcoming 'Diffusion Limits' - Principles required to measure high molar mass polymers by diffusion ordered NMR.

Thomas Swift1, Edward Dyson1, Natalia Koniuch1

  • 1Polymer and Biomaterials Chemistry Laboratory, Department of Chemistry and Biosciences, University of Bradford, Bradford, BD7 1DP, United Kingdom.

Analytica Chimica Acta
|April 10, 2025
PubMed
Summary

Accurately measuring polymer size with diffusion NMR requires accounting for in-solution viscosity. This study shows how to correct for viscosity effects, enabling precise determination of hydrodynamic radius for large macromolecules.

Keywords:
DOSYHydrodynamic radiusPolymersViscosity

More Related Videos

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry
06:56

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

Published on: June 10, 2018

24.9K
Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study
10:10

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study

Published on: August 15, 2016

10.2K

Related Experiment Videos

Last Updated: May 15, 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

7.8K
Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry
06:56

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

Published on: June 10, 2018

24.9K
Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study
10:10

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study

Published on: August 15, 2016

10.2K

Area of Science:

  • Polymer Chemistry
  • Analytical Chemistry
  • Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

  • Diffusion NMR is increasingly used for polymer size analysis.
  • In-solution viscosity complicates NMR output, requiring specialized methods.
  • Accurate hydrodynamic radii determination is crucial for high molar mass or dispersity polymers.

Purpose of the Study:

  • To investigate the impact of in-solution viscosity on polymer size determination using DOSY NMR.
  • To develop and validate methodologies for accurate hydrodynamic radii measurements of macromolecules.
  • To expand the applicability of diffusion NMR to high molar mass and high viscosity systems.

Main Methods:

  • Utilized diffusion measurements via DOSY NMR across a range of polymer types and solvents.
  • Employed a viscosity correction factor applied to pure solvent viscosity to determine in-solution viscosity.
  • Investigated the performance of a diffusion-optimized NMR probe (Bruker DiffBB).

Main Results:

  • Hydrodynamic radii determined for various polymers (PEG, PEO, PS, PMMA, PNIPAM) showed high accuracy compared to literature values.
  • In-solution viscosity significantly impacts diffusion NMR outputs, with higher variability in low-viscosity solvents.
  • The experimental range was extended to polymers with molar masses exceeding 1 million g/mol and high-viscosity solutions.
  • A diffusion-optimized NMR probe effectively targeted slowly diffusing chemical species.

Conclusions:

  • In-solution viscosity, influenced by even small amounts of high molar mass polymers, causes systematic offsets in diffusion NMR data.
  • DOSY NMR measurements, by including solvent diffusion, can self-correct for these viscosity effects.
  • This approach allows for accurate prediction of hydrodynamic radius and molar mass for large, slowly diffusing materials without external standards.