The strip was stretched at a rate of 50 mm/min and stopped after the material broke. This was repeated at least three times with each material. The diodes were also tested with a clamping distance of 30 mm, but they were stretched incrementally. At each increment, a voltage sweep was performed at a rate of 0.2V every 0.1 s from -2.6 V to 2.6 V, and Ag/AgCl electrodes were used to interface with the PEDOT:PSS hydrogel. For the strain stiffening device, a cyclic program was used that travelled at a rate of 50 mm/min and reached a maximum of 70% strain.