Dual Thermo-Responsive and Strain-Responsive Ionogels for Smart Windows and Temperature/Motion Monitoring

In this work, a stretchable, dual thermo-responsive and strain-responsive ionogel has been synthesized by one-step photopolymerization. The obtained ionogel shows an ultrahigh stretchability (∼3000%), a high ionic conductivity (up to 3.1 mS/cm), and a good temperature tolerance (-40 to 300 °C). Importantly, these ionogels show an upper critical solution temperature-type phase transition with a wide tunable phase-transition temperature (17.5-42.5 °C) and reversible color/transparency switching. In particular, the as-prepared ionogel-based flexible/wearable temperature monitors and smart windows show an excellent designability and programmability, temperature modulation ability, and thermal responsiveness. Moreover, the ionogels-based strain sensors have temperature- and strain-dual responsibility and a broad strain-sensing range (1-700%), which can effectively monitor various motions. This strategy of fabricating dual thermo- and strain-responsive ionogels by using a one-step method and only one polymer holds great promise for the next generation of multifunctional stimuli-responsive materials.