Researchers have developed a rubber fiber/nano-particles conductive nano composite, which can be used to create bendable and strechable electronic devices. For development of bendable and pullable electronic devices, it is critical to develop stretchable electrodes that maintain their electrical properties and remain stable with physical deformation like bending and elongation. However it has been difficult to secure two specifications at the same time because high conductivity and stretchability are mutually exclusive parameters.

Any stretchable electrodes developed so far could not be easily applied in devices because they could not maintain sufficient conductivity and form fine patterns at large strains. Moreover, the ability to make arbitrary patterns over large areas was also desirable.

Professor UnRyong Jeong (Yonsei University) and and Dr. JongJin Park (Samsung Advanced Institute of Technology) introduced a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications.

According to the researchers, a silver nanoparticle precursor is absorbed in electrospun poly styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat.

Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ ≈ 2,200 S cm-1 at 100% strain for a 150-µm-thick mat).

The researches have managed to design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricated a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.

The researchers plan to further advance the technology to allow the development of wearable electronics, textile electronics, and e-skin sensors.