Fig. 1. Fabrication of Ga-LM based flexible electrons by laser and its applications^[44-49]

Fig. 2. Wettability model of Ga-LM. (a) Characterization of static contact angle; (b) advancing angle, receding angle and rolling angle for contact angle hysteresis phenomenon; (c) wettability of water and Ga-LM droplets at super-hydrophilic surface; (d) wettability of water and Ga-LM droplets at super-hydrophobic surface

Fig. 3. Tuning wettability of Ga-LM by laser ablating nanoparticles ^[90]. (a) Sequential optical images of pressing down and lifting up process of Ga-LM droplet on bare glass and silica nanoparticles coated glass; (b) detailed fabrication steps of Ga-LM patterning process; (c) images of various Ga-LM patterns on different substrates

Fig. 4. Wettability test of Ga-LM and circuit preparation strategy. (a) Wettability test of Ga-LM on smooth and rough surfaces ^[93]; (b) preparation steps and electrical performance test of Ga-LM circuit ^[56]; (c) preparation of Ga-LM circuits on different materials ^[94]; (d) preparation of Ga-LM flexible integrated circuit^[95]

Fig. 5. Magnetic field driven Ga-LM circuit and demonstration of its application in tension sensing ^[31]. (a) Magnetic field driven Ga-LM printed circuit principle; (b) GLM lines with different widths; (c) characterization of resistance stability when driving Ga-LM repair circuits; (d) demonstration of its application in tension sensing

Fig. 6. Preparation of high-performance Ga-LM based pressure sensor ^[32]. (a) Concept diagram of Ga-LM based pressure sensor; (b) Ga-LM printing quality improved by surface covering with sacrificial layers; (c) elaborate patterns prepared by covering sacrificial layers

Fig. 7. Ga-LM based flexible patch antenna ^[47]. (a) Structural model diagram of Ga-LM based flexible patch antenna；physical maps of (b) original and (c) bent flexible patch antennas; (d) working frequency test of flexible patch antenna under different bending curvatures; (e) bending resistance test of flexible patch antenna

Fig. 8. Transfer printing method to realize printing of Ga-LM on complex irregular surfaces ^[33]. (a) Adhesion test of Ga-LM on smooth and laser-induced rough surfaces; (b) transfer principle of Ga-LM on substrate surface; (c) flow chart of laser transfer of Ga-LM; (d) display of transfer results on various complex irregular surfaces

Fig. 9. Laser fabrication of Ga-LM multilayer circuit ^[96]. (a) Application concept diagram of Ga-LM multilayer circuit; (b) structural model diagram of Ga-LM multilayer circuit; (c) flow chart of laser preparation of Ga-LM multilayer circuit

Fig. 10. Preparation principle and results of Ga-LM based tilt position sensor ^[48]. (a) Laser preparation of super-metalphobic surfaces of LIG/PDMS; (b) adhesion test of Ga-LM on PDMS, LIG/PDMS, and laser-induced LIG/PDMS; (c) contact model of Ga-LM droplets on rough LIG/PDMS surface; (d) principle model demonstration and (e) physical map of Ga-LM based tilt position sensor

Fig. 11. Ga-LM based flexible electronics for health monitoring. (a) Ga-LM based flexible electronics to monitor tilt, respiration, and humidity of infant^[48]; (b) monitoring of cycling center rate by Ga-LM based flexible electronics^[101]; (c) Ga-LM fiber felt used to measure electrocardiography signals^[102]

Fig. 12. Human-computer interaction with Ga-LM based flexible electronics ^[49]. (a) Structural model diagram of multilayer Ga-LM electron transfer tattoo; (b) physical map of multilayer Ga-LM electron transfer tattoo; (c) application demonstration of multilayer Ga-LM electronic transfer tattoo in human-computer interaction

Fig. 13. Ga-LM based robot ^[108]. (a) Bionic inchworm flexible robot based on Ga-LM; (b) structural design and continuous motion snapshot of Ga-LM droplet driven wheel robot

Table 1. Comparison of representative stretchable conductive materials