
Video shows particle engulfment to create soft electronics
Researchers in Singapore and the US have developed a printing technique to add functional particle to polymers to create stretchable soft electronics.
This technique can be used to create multilayered, multimaterial and elastic devices with wireless sensing, communication and power transfer capabilities.
Current approaches to fabricating such materials require that the particles be first colloidally dispersed in a liquid monomer or polymer solution that have limited material compatibilities and require precise control over the associated fluid mechanics during the printing process.
Instead the technique incorporates the functional particles directly into the polymers using particle engulfment, a process in which particles are spontaneously subsumed by the polymer matrix via surface energy to create the soft electronics. The relies on designing the particles and the polymer substrate with precise sizes and surface energy to allow the process.
The engulfment phenomenon occurs when the characteristic size of the particles is much smaller than the elastocapillary length of the polymer matrix. This results in an energetically stable configuration where functional particles are engulfed and become deeply embedded into the polymer.
The team from the National University of Singapore and Rice University in the US used carbon nanotubes to create a strain sensor connected to an RFID wireless interface.
“We used the approach to fabricate intrinsically stretchable devices based on polymeric electronic materials that can potentially achieve higher component density and better mechanical ductility, but remain scarce because existing materials typically sacrifice electronic performance for stretchability,” they said.
Engulfment for soft electronics
