Photo-Induced Reversible Deformation of Liquid Metal/Azo Polymer Hybrid Nanospheres for Application as Transformable Nanomachine

Liquid metal can be used in transformable soft robots due to its ability to manifest universal deformation effects under external field stimuli. However, the reversible transformation of liquid metals between different forms under the control of light fields has not been sufficiently investigated. In this work, a method to coat liquid metal nanodroplets with an azo polymer that exhibits photo-induced deformation properties has been developed. The azo polymer corona surrounding the liquid metal nanodroplets imparts the photo-induced deformation properties to the liquid metal. By alternating illumination to the liquid metal/azo polymer hybrid nanospheres with 488 nm polarized light and 980 nm light, the nanospheres can undergo a reversible transformation between spheres and ellipsoids. The interaction between liquid metal nanodroplets and the azo polymer shell is investigated by using density functional theory. This photo-induced reversible deformation successfully overcomes the limitations of the liquid metal itself in responding to external light stimuli, providing potential application as transformable nanomachine.