TOWARDS THE DESIGN OF STRECHABLE ENCAPSULANTS FOR SELF-HEALING LIQUID METAL-BASED ELECTRONICS USING BLENDED DIELS-ALDER NETWORKS

Activity: Talk or presentationTalk or presentation at a conference

Description

The wide recognition of cutting-edge liquid metal-based soft electronics made with self-healing polymer materials stems from their unique combination of flexibility, high electrical conductivity, self-healing properties, and adaptability which not only enable a wide range of innovative applications but also satisfy the sustainability issues. In this study, a robust method is explained for the effective encapsulation of liquid metals by the development of certain polymer elastomers that prosperously balance the trade-off between the mechanical flexibility and impermeability of the encapsulant against water and oxygen. To take advantage of various chemistries that each can desire only one of the required properties, two different polymers, one polyether amine FD4000, and the other aminopropyl polydimethylsiloxane FS5000,both possessing4 furan groups were mixed and further reacted with bismaleimide DPBM to construct dynamic polymer networks with intrinsic self-healing capabilities. The thermo-reversible Diels-Alder reaction between furan and maleimide reacting groups by which the blended networks were formed, warranted the good compatibility of two immiscible backbones. Altering the composition of two backbones in the explained system from 75/25 to 50/50 and 25/75 for FD4000 and FS5000 respectively (primary and secondary phases) led to the evolution of phase-separated blends in which the morphology is mainly controlled by the concentration of backbones. Starting from 25% FS5000, a dilute droplet morphology forms. By increasing the content of FS5000 to 50% or 75%, the growing concentration of droplets in the blend 5050 builds a layer of hydrophobic polydimethylsiloxane which is impermeable against water. On the other hand, the presence of the polypropylene oxide backbone with a more hydrophilic nature inherently enhanced the resistance of the blended encapsulants to the diffusion of oxygen. In addition to adjusting the hydrophobicity of networks for their barrier properties against both water and oxygen the blending allowed tuning of the mechanical properties. For instance, FD4000 contributed to a higher stretchability while FS5000 improved the hysteresis and creep resistance of the blends. Moreover, manipulating the concentration of crosslinker impacted the network properties. Decreasing this stoichiometric ratio from r=0.7 to r=0.6 or r=0.5 increases the chain mobility and favors mechanical flexibility and more importantly, self-healing properties at room temperature. Finally, the self-healing sensors fabricated with Galinstan and the best Diels-Alder blended network exhibited promising electromechanical response and efficient recovery after damage-healing cycles.
Period31 May 2031
Event titleAnnual Meeting of Belgian Polymer Group 2024
Event typeConference
LocationBlankenberge, Belgium
Degree of RecognitionNational