Thermal Conductivity of PAAm Hydrogel and its Crosslinking Effect

TL;DR

This study investigates how the thermal conductivity of polyacrylamide (PAAm) hydrogels can be tuned by adjusting crosslinking density, combining experimental measurements and molecular simulations to understand heat transfer in soft, biocompatible materials.

Contribution

It provides the first detailed analysis of how crosslinking density affects thermal conductivity in PAAm hydrogels using combined experimental and simulation approaches.

Findings

Thermal conductivity varies from 0.33 to 0.51 W/m·K with crosslinking density.

Increased crosslinking enhances conduction pathways but also increases phonon scattering.

The study offers insights for designing hydrogel-based thermal management devices.

Abstract

As the interface between human and machine becomes blurred, hydrogel incorporated electronics and devices have emerged to be a new class of flexible/stretchable electronic and ionic devices due to their extraordinary properties, such as soft, mechanically robust and biocompatible. However, heat dissipation in these devices could be a critical issue and remains unexplored. Here, we report the experimental measurements and equilibrium molecular dynamic (EMD) simulations of thermal conduction in polyacrylamide (PAAm) hydrogels at room temperature. The thermal conductivity of the PAAm hydrogels can be modulated from 0.33 to 0.51 Wm-1K-1 by changing the crosslinking density. The crosslinking density dependent thermal conductivity in hydrogels is explained by the competition between the increased conduction pathways and the enhanced phonon scattering effect. The assumption is further supported by both the equilibrium swelling ratio measurement and molecular simulation of hydrogels. Our study offers fundamental understanding of thermal transport in soft materials and provides design guidance for hydrogel-based devices.