Heterogeneous Structural Color Conductive Photonic Organohydrogel Fibers with Alternating Single and Dual Networks

Intelligent interactive electronic devices can dynamically respond to and visualize various stimuli, promoting the rapid development of flexible electronics. In this paper, an alternating single- and dual-network design strategy was developed for ingeniously constructing an interactive electronic fiber sensor with heterogeneous structural color (HSCEF sensor). The resulting sensor can rapidly output the synchronous electrical and optical dual signals under strain by adjusting the transport distance of conductive ions and the lattice spacing of the photonic crystal (∼200 ms). Meanwhile, the addition of low-freezing-point glycerol endowed the HSCEF sensor with excellent low-temperature tolerance (-25 °C) and cyclic stability. Notably, benefiting from the alternating single- and dual-network structure, the HSCEF sensor exhibits attractive heterogeneous structural color, which achieves colorimetric changes in the full visible light region with high mechanochromic sensitivity (2.25 nm %^-1) and large wavelength shift (Δλ ∼ 225 nm). An intelligent wearable interactive sensor is finally used for real-time dynamic detection of joint movements, realizing precise resolution of different amplitudes. This work provides a general strategy to transform conventional photonic gels into heterogeneous structural color ones, and the developed new interactive sensor with rich optical information could be further used for visual health and exercise monitoring, intelligent soft robotics, wearable sensors, etc.