Smart Core-Shell Elastomer Fibers with Simultaneous Resistance and Color Responses

Fibers with deformation-triggered responses are essential for smart textiles and wearable electronics. Here, smart core-shell elastomer fibers with a conductive core and a liquid crystal elastomer shell showing simultaneous resistance and color responses are designed and prepared. The conductive core is consisted of interconnected liquid metal nanodroplets dispersed in a polymer matrix and the elastomer shell is made of cholesteric liquid crystals. When stretched, the fiber resistance increases as the interconnected pathways of liquid metal nanodroplets along the fiber axis become narrower, and the selective reflection color from the fiber surface blueshifts since the cholesteric pitch decreases. The smart elastomer fibers could be woven into smart textiles and respond to various mechanical deformations, including stretching, bending, compression and twisting. The average resistance change is 51% under 100% strain and its variation is smaller than 4% over 500 cycles, showing remarkable fatigue resistance. The simultaneous resistance and color responses to mechanical deformations make the fibers attractive for broad applications, such as flexible electronics.