Localized and Collective Dynamics in Liquid-like Polyethylenimine-Based Nanoparticle Organic Hybrid Materials

In this work, broadband dielectric spectroscopy, rheology, and nuclear magnetic resonance spectroscopy are employed to study molecular dynamics in a nanoparticle organic hybrid materials(NOHMs)system comprising 20 wt% silica nanoparticles ionically-bonded to a polyethylenimine canopy. By comparing t...

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Bibliographic Details
Published in:Macromolecules 2021-02, Vol.54 (5)
Main Authors: Mapesa, Emmanuel Urandu, Cantillo, Nelly M., Hamilton, Sara T., Harris, Matthew A., Zawodzinski, Jr., Thomas A., Alissa Park, Ah-Hyung, Sangoro, Joshua
Format: Article
Language:English
Subjects:
Hybrid materials
Insulators
MATERIALS SCIENCE
Nanoparticles
Polyethylenimine
Polymers
Online Access:Get full text
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Summary:In this work, broadband dielectric spectroscopy, rheology, and nuclear magnetic resonance spectroscopy are employed to study molecular dynamics in a nanoparticle organic hybrid materials(NOHMs)system comprising 20 wt% silica nanoparticles ionically-bonded to a polyethylenimine canopy. By comparing the neat polymer (used as a canopy) to the derivative NOHMs, we find that timescales characterizing segmental dynamics in the NOHM are identical to those for the neat polymer. Detailed analysis of the carbon-spin lattice relaxation times yields mechanistic insights into localized and collective dynamics, in quantitative agreement with dielectric results. Interestingly, the NOHMs retain liquid-like characteristics unlike conventional polymer nanocomposites but exhibit higher viscosity due to additional contributions from tethered polymer chains, and mesoscopic structuring. These findings demonstrate the potential of achieving unique and desired material properties via NOHMs by an informed choice of the canopy material.
ISSN:0024-9297
1520-5835