Strain-induced conductive network and memory effect of maximum strain in liquid metal hierarchical structure

[Display omitted] •The memory effect of maximum strain in hierarchal liquid metal network is proposed.•The effect relies on the successive rupture and the formed wrinkle structure of liquid metal particles.•Particle size and particle position could offer adjustment for memory effect.•Liquid metal particles are innovatively fabricated by two-step physical vapor deposition. Liquid metals based on gallium have attracted considerable attention for flexible electronics, thanks to their excellent combination of stretchability and conductivity. Nevertheless, the degradations of electrical properties under deformation and effective tune of electrical resistance like a rheostat remain problems to be solved. Herein, a hierarchical structure of liquid metal particles is prepared by the combination of oxidation process and two-step physical vapor deposition. Owing to the rupture of particles, the electromechanical response allows resistance to irreversibly decrease in response to increased tensile strains and remain constant during strain release. Furthermore, the rupture level of core–shell structural particle can be controlled by the applied strain, resulting in strain-induced electrical properties. Notable characteristics include memory effect of maximum strain. As long as the strain is smaller than the maximum strain experienced previously, the strain-induced conductive network maintains nearly constant resistances to cyclic deformations (R/R0