Minimally invasive devices that can bend and stretch in all directions—that is, seamlessly move with the body—are a compelling component of future biomedical applications. Now that future is closer to reality, thanks to the work of scientists at the Henry Samueli School of Engineering and Applied Science at the University of California Los Angeles (UCLA). They have demonstrated for the first time a light-emitting device that is “intrinsically stretchable”—meaning every part of the device can be stretched: The metal-free devices can be linearly stretched up to 45%, and the composite electrodes can be reversibly stretched even more—up to 50%—with little change in sheet resistance.1
|An emissive polymer light-emitting device operating at 8 V undergoes strains of 0% (left), 20% (center), and 45% (right). (Image courtesy of UCLA)|
The researchers developed a simple process to fabricate the transparent devices using single-walled carbon nanotube polymer composite electrode. The process involves roll lamination of two composite electrodes that sandwich an emissive polymer layer. Together, the interwoven networks of nanotubes and the polymer matrix in the surface layer of the composites enable low surface roughness along with high transparency and compliance.
1. Z. Yu et al., Adv. Mat., doi: 10.1002/adma.201101986 (2011).