Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Polymers: Molecular Weight Distribution

Polymers: Molecular Weight Distribution

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.

Molecular Weight of Step-Growth Polymers

Molecular Weight of Step-Growth Polymers

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...

Polymer Classification: Crystallinity

Polymer Classification: Crystallinity

Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...

Polymers: Defining Molecular Weight

Polymers: Defining Molecular Weight

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...

¹H NMR: Complex Splitting

¹H NMR: Complex Splitting

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...

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

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

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.

You might also read

Related Articles

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

Sort by

Same author

Tracking the Early Hydration Reaction of Cementitious Calcium Silicate Hydrate via DNP-Enhanced Solid-State NMR.

Journal of the American Chemical Society·2026

Same author

Insights into Cationic Vacancies in a Prussian Blue Analogues Cathode for Enhanced Reversible Sodium Insertion.

JACS Au·2026

Same author

Mapping mRNA Localization and Internal Structure in Lipid Nanoparticles through Solid-State Dynamic Nuclear Polarization NMR and Proton Spin-Diffusion Modeling.

Small methods·2026

Same author

In Situ Light-Induced Degradation of Hybrid Perovskites by NMR Spectroscopy.

Journal of the American Chemical Society·2026

Same author

Fluorinated Biradicals for <sup>19</sup>F Magic-Angle Spinning Dynamic Nuclear Polarization-Enhanced NMR Spectroscopy.

Journal of the American Chemical Society·2026

Same author

Origin of the Unusual Narrowband Near-Infrared Emission from Cr<sup>3+</sup>-Doped Oxides.

Journal of the American Chemical Society·2026

Search research articles

Related Experiment Video

Updated: Mar 30, 2026

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Published on: September 8, 2016

A solid-state NMR method to determine domain sizes in multi-component polymer formulations.

Judith Schlagnitweit¹, Mingxue Tang¹, Maria Baias¹

¹Université de Lyon, Institut de Science Analytiques, Centre de RMN à très hauts champs (CNRS/ENS Lyon/UCB Lyon1), Villeurbanne, France.

Journal of Magnetic Resonance (San Diego, Calif. : 1997)

|November 4, 2015

Summary

This summary is machine-generated.

This study introduces a new solid-state Nuclear Magnetic Resonance (NMR) method to measure polymer domain sizes in complex mixtures. The technique is effective for analyzing pharmaceutical controlled-release formulations, aiding in material characterization.

Keywords:

Cellulose Domain sizes Solid-state NMR Spin diffusion

More Related Videos

Application of Voltage in Dynamic Light Scattering Particle Size Analysis

Application of Voltage in Dynamic Light Scattering Particle Size Analysis

Published on: January 24, 2020

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Published on: August 22, 2015

Related Experiment Videos

Last Updated: Mar 30, 2026

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Published on: September 8, 2016

Application of Voltage in Dynamic Light Scattering Particle Size Analysis

Application of Voltage in Dynamic Light Scattering Particle Size Analysis

Published on: January 24, 2020

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Published on: August 22, 2015

Area of Science:

Polymer Science
Materials Science
Analytical Chemistry

Background:

Polymer domain sizes significantly influence material properties.
Accurate measurement of these domains is crucial for material development.
Existing methods may have limitations in analyzing complex multi-component polymer systems.

Purpose of the Study:

To develop and present a novel solid-state Nuclear Magnetic Resonance (NMR) experiment.
To enable the measurement of domain sizes in multi-component polymer mixtures.
To apply this method to challenging pharmaceutical controlled-release formulations.

Main Methods:

Utilizes selective excitation of carbon magnetization to isolate specific polymer components.
Employs proton spin diffusion as a mechanism to report on domain size.
Applies the technique to industrial pharmaceutical formulations containing cellulose derivatives.

Main Results:

Successfully demonstrates a solid-state NMR method for measuring polymer domain sizes.
Quantifies domain sizes in complex pharmaceutical formulations, including microcrystalline cellulose matrixes coated with ethyl cellulose (EC) and hydroxypropyl cellulose (HPC).
The method operates effectively at natural isotopic abundance.

Conclusions:

The presented solid-state NMR technique is a powerful tool for characterizing domain sizes in multi-component polymer systems.
This method offers a valuable approach for analyzing pharmaceutical controlled-release formulations.
The ability to measure domain sizes at natural abundance simplifies sample preparation and analysis.