Stimuli-responsive twist actuators made from soft elastic composite materials -- linking mesoscopic and macroscopic descriptions

TL;DR

This paper develops a multiscale modeling approach linking mesoscopic particle arrangements to macroscopic twist actuation behavior in soft elastic composite materials like magnetorheological gels and elastomers.

Contribution

It introduces a framework to connect mesoscopic models with macroscopic descriptions, enabling understanding of twist actuation in soft composites from particle-level to system-level.

Findings

Derived expressions linking mesoscopic parameters to macroscopic behavior

Applicable to magnetorheological gels and elastomers

Provides a basis for mapping observed macroscopic responses to microscopic structures

Abstract

Very recently, the construction of twist actuators from magnetorheological gels and elastomers has been suggested. These materials consist of magnetizable colloidal particles embedded in a soft elastic polymeric environment. The twist actuation is enabled by a net chirality of the internal particle arrangement. Upon magnetization by a homogeneous external magnetic field, the systems feature an overall torsional deformation around the magnetization direction. Starting from a discrete minimal mesoscopic model set-up we work towards a macroscopic characterization. The two scales are linked by identifying expressions for the macroscopic system parameters as functions of the mesoscopic model parameters. In this way, the observed behavior of a macroscopic system can in principle be mapped to and illustratively be understood from an appropriate mesoscopic picture. Our results apply equally well to corresponding soft electrorheological gels and elastomers.