Broadband dielectric spectroscopy, rheology, nuclear magnetic resonance spectroscopy and X-ray scattering are employed to study dynamics and structure in a nanoparticle organic hybrid material system comprising 20 wt% silica nanoparticles ionically-bonded to a polyethylenimine canopy (NOHM-I-PEI). 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.

Elucidating structure and dynamics in nanoparticle organic hybrid materials (NOHMs)

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.