Preparation of liquid metal microrobots with an asymmetric core–shell structure for thermal gradient navigation†

Soft microrobots capable of sensing and responding to localized physical stimuli offer a fuel-free route to autonomous propulsion, opening new opportunities for targeted therapeutic applications in biomedicine. Herein, we propose a thermo-responsive microrobot featuring an asymmetric core–shell structure composed of an eccentric liquid metal (LM) core and a polyacrylic acid (PAA) shell. The combination of asymmetric structure and the contrasting thermal conductivities of the LM core (high) and PAA shell (low) enables thermophoretic capability, which achieves directional motion under localized thermal gradients without the need for chemical fuels.