“…Also, they offered very advanced technological solutions for robotics and wearable systems. From a mechanical point of view, flexible and stretchable substrates were chosen, while the integrated components went from rigid (Yang et al, 2010;Kim et al, 2011;Xu et al, 2014) to semi-rigid (Engel et al, 2005;Yang et al, 2008) and finally to flexible (Tien et al, 2014;Park et al, 2015;Zhang et al, 2015) and stretchable (Someya et al, 2004;Sekitani et al, 2008;Park et al, 2014;Chou et al, 2015) devices.…”