Materials by Design for Stiff and Tough Hairy Nanoparticle Assemblies

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Assembled hairy nanoparticles (aHNPs) improve nanocomposite thermomechanical performance by enhancing dispersion and interfacial interactions.
• Achieving optimal stiffness and toughness simultaneously in aHNPs is challenging due to conflicting properties and numerous design parameters.

Purpose of the Study:

• To develop a computational framework for optimizing aHNP mechanical properties.
• To establish design strategies for enhancing both stiffness and toughness in polymer-grafted nanocrystal nanocomposites.

Main Methods:

• Combined multiresponse Gaussian process metamodeling and coarse-grained molecular dynamics simulations.
• Utilized a poly(methyl methacrylate) grafted cellulose nanocrystal system as a model.
• Analyzed the influence of polymer chain length, grafting density, nanoparticle size, and interfacial interactions.

Main Results:

• Polymer chain length and grafting density were identified as primary factors influencing aHNP mechanical properties.
• Optimal properties were achieved above 60% nanoparticle weight percentage and when grafted chains exceeded the critical length for the semidilute brush regime.
• Theoretical scaling relationships from the Daoud-Cotton model accurately predicted critical length dependence on graft density and nanoparticle size.

Conclusions:

• The developed framework provides molecular-level insights into aHNP mechanical behavior.
• Guidelines for designing nanocomposites with superior mechanical properties were established.
• This approach facilitates the tailored design of advanced polymer-nanocrystal materials.