Work

Glassy interphases reinforce elastomeric nanocomposites by enhancing volume expansion under strain

Year: 2026

Type: article

Abstract: For nearly a century, introduction of nanoparticles to elastomers has yielded extraordinarily tough nanocomposites that are critical to technologies from actuators to tires. The mechanisms by which this reinforcement occurs have nevertheless remained a central open question in material science. One widely debated hypothesis posits that strong interactions between polymer and particles induce "glassy bridges" that cement particles into a cohesive percolating network that resists elongation. Here, molecular dynamics simulations show that glassy particle shells do not primarily provide elongational cohesion. Instead, they amplify an underlying mechanism wherein competition between filler and elastomer networks causes the elastomer's volume to increase on deformation. This induces contributions from the elastomer's bulk modulus, which is of order 1,000 times larger than its Young's modulus. These findings establish a unified understanding of low-strain reinforcement in filled elastomers as emanating from volumetric competition between coexisting particulate and elastomeric networks. This reframes and unifies our understanding of low-strain reinforcement, provides a clear-cut diagnostic for the presence of glassy bridging, and offers a design principle for tough elastomeric nanocomposites.

Source: Proceedings of the National Academy of Sciences

DOI: 10.1073/pnas.2528108123

Authors: Pierre Kawak, Harshad Bhapkar, David S. Simmons

Institution: University of South Florida

Language: English

Topic: Polymer Nanocomposites and Properties

Subfield: Polymers and Plastics

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Funder: Basic Energy Sciences

Award: G6161661839