Network Disassembly Spectrometry (NDS)

For Quantifying Topological Loop Defects in Polymer Networks

​

By Juan A. Cintron-Cruz

Prof. Jeremiah Johnson, MIT

Updated: September 2023

Quantifying Topological Defects in Polymer Networks

Goal: To characterize connectivity defects (primarily primary loops and dangling unreacted functionalities) in polymer networks.

25. Gu et. al Angew. Chem. Int. Ed. 2020, 59, 5022.

M. Zhong et. al Science 2016, 353, 1264.

25. A. Arora et al. Macromolecules 2020, 53, 7346.

Network Disassembly Spectrometry (NDS) – Mass Labels

x

n

x

n

x

i

x

i

i

n

x

= Reactive A Groups

= Mass Labels

= Cleavable Site

Mix of Labelled and Non-Labelled A₂ Degradable Polymer Strands

A+B End-Linking

Reaction

Some Possible

Junction Patterns

(Assuming full conversion)

Network Disassembly via x Cleavage

​

= Reactive B Groups

x

x

p_non-loop

p_loop

NDS Data - Liquid Chromatography/Mass Spectrometry Analysis

LC/MS Spectra of the Junctions Obtained After Network Disassembly

Loops!

From MS

Junctions Concentration for A₂+B₃ Networks:

K. Kawamoto et al. Macromolecules 2015, 48, 8980–8988.

J. Wang et. al Chem. Sci. 2019, 10, 5332.

NDS in Vulcanized/Side-Chain Crosslinked Networks

Loops/Intramolecular Crosslinks!

Junctions Concentration for A₂+B_f Networks:

Examples of Mass Labelling Strategies Used in NDS

Some Mass Labelling Strategies

Mass Labelled Polymer Strands for End-Linked Gels

Mass Labelled Primary Chains for Vulcanized Networks

H. Zhou et al. J. Am. Chem. Soc. 2014, 136, 9464−9470.

K. Kawamoto et al. Macromolecules 2015, 48, 8980–8988.

J. Wang et. al Chem. Sci. 2019, 10, 5332.

​

Limitations, Caveats, and Practical Considerations

Contact: Juan A. Cintron-Cruz

Johnson Lab

jcintron@mit.edu or Slack

Advantages:

• high sensitivity, very small amounts of materials needed (<200uL gels).
• gives precise measurement of dangling chains and primary loops without any additional fittings.
• versatile method which can be applied to many crosslinked polymeric materials and soluble branched polymers.

​

Caveats and Limitations:

• requires slight modifications of the system to introduce mass labels and cleavable sites.
• not suitable for chain-growth networks yet (e.g. networks from FRP, etc).