Multi-scale non-affine mechanics of electro-magneto-active elastomers: Taut domain exploitable convolution of polymer chain crosslinks, entanglements and finite extensibility

Abstract

Actuation devices fabricated using smart polymers often exhibit wrinkling and pull-in instability when they are subjected to external stimulation. These instabilities can disrupt the intended functionality of the actuation devices and hinder their reliability. The underlying reason for these instabilities is the complicated architecture of the polymer network, which results in a complex and chaotic arrangement of crosslinks and entanglements in smart elastomer membranes. This convoluted structure significantly influences the mechanical behavior of the polymers when external forces are applied. To better understand and characterize these instability phenomena, the present study develops a physics-based non-affine material model incorporating the effects of critical factors like polymer chain crosslinks, entanglements, and finite extensibility. By considering the intricate interplay among these factors, the model provides fundamental insights into the mechanisms behind the instability phenomena in smart polymers. Subsequently, the study explores the relationship between the applied electromagnetic field and the taut domains. The findings reveal that the size of the taut domains can be effectively altered by manipulating the levels of polymer chain crosslinks, entanglements, and finite extensibility. It is observed that, for a given level of applied electromagnetic field, increasing the entanglement and crosslink parameter leads to a larger taut domain. Conversely, an increase in the finite extensibility of the polymer chain diminishes the taut domain under the same level of electromagnetic loading. These understandings open up new avenues for optimizing actuation devices by adjusting the intricate properties of polymer chains to enhance stability and performance by unlocking the full multi-physical potential of smart elastomers. © 2025 Elsevier B.V., All rights reserved.