Optimization of conductive elastomeric composites for directly printed intrinsically stretchable conductors

Abstract

Intrinsically stretchable solid-state conductors can shed light on the realization of further biocompatible and reliable wearable electronics. However, their material composition should be optimized considering the compatibility of target stretchable platforms. In this paper, we report directly printable conductive elastomeric composites for intrinsically stretchable conductors. Pneumatic direct ink writing (DIW) system is employed to deposit well-defined patterns. Polydimethylsiloxane (PDMS), Ag particles, and multi-walled carbon nanotubes (MWCNTs) were used as elastomeric matrix, conductive filers, and auxiliary fillers, respectively. Because there is a critical trade-off between the conductivity and stretchability depending on the concentration of conductive fillers, we optimize the Ag concentration to 77.5 wt% to fulfill these requirements. Especially, we introduce multi-solvent Ag composite inks to deliver excellent printability and enhanced conductivity simultaneously. We further investigate the electromechanical reliability of the encapsulated conductors undergoing cyclic strains, and they exhibited stable R/RO values over 50% strain.

3D-Printed Soft Temperature Sensors Based on Thermoelectric Effects for Fast Mapping of Localized Temperature Distributions

“…19,30,31 In this regard, the automated 3D printing process emerges as a powerful solution, enabling the customization of TE arrays with high resolution tailored to the shape and structure of the applications. 32,33 This customization can be achieved using rheology-modulated materials, which range widely from inorganic substances to polymers. 34−36 Most notably, the 3D printing process can facilely fabricate 3Dstructured TE modules in an additive manner.…”

“…Recently, several studies have reported strategies to modify device designs, such as introducing wavy or origami structures to overcome the associated limitations of planar-type modules and highly integrated TE arrays. These modifications, however, often require additional post-structural deformation processes. ,, In this regard, the automated 3D printing process emerges as a powerful solution, enabling the customization of TE arrays with high resolution tailored to the shape and structure of the applications. , This customization can be achieved using rheology-modulated materials, which range widely from inorganic substances to polymers. − Most notably, the 3D printing process can facilely fabricate 3D-structured TE modules in an additive manner. This capability is crucial for developing temperature sensors capable of imposing temperature gradients in the out-of-plane direction when placed on target surfaces, thereby enhancing the detection of temperature changes.…”