In practical application, repeated stretching and contact of elastomer will lead to material surface damage. These small damages may cause significant damage in optical and mechanical properties. Because of the dynamic reversibility of the crosslinking network between Fe3O4 @ CNP and amino terminated polymer chain, Fe3O4 @ C / PDMS PE can recover itself when damaged. In addition, Fe3O4 @ CNP can also improve the healing performance of the damaged area by effectively absorbing light and converting it into heat, which can be used as a local heat source and improve the mobility of polymer chain. When the laser irradiation intensity of Fe3O4 @ C / PDMS PE40 is 0.254 W, the temperature immediately increases by 100 ℃, indicating that the introduction of Fe3O4 @ CNP gives PE excellent photothermal properties. The incision of Fe 3O 4@C/PDMS PE40 disappeared after 2 hours of NIR laser irradiation with 0.254 W intensity,
The maximum tensile strength can be restored to 53% of the original strength.
In addition, sunlight can also be used to accelerate the healing performance of PE. Under the simulated solar radiation, the temperature of Fe3O4 @ C / PDMS PE40 increases with time, and finally reaches the equilibrium value (the highest temperature is about 93 ℃).
Fig. 4 repairability of Fe3O4 @ C / PDMS PE. a) The temperature of amino PDMS and Fe3O4 @ C / PDMS PE 40 varied with time under different intensity of laser irradiation (808 nm). b) The optical microscope images of two contacted PE and C) healed under 808 nm laser irradiation for 2 hours. d) The reflection spectra of the original and repaired Fe3O4 @ C / PDMS PE irradiated by 808 nm laser for 2 hours. e) The temperature of amino PDMS and Fe3O4 @ C / PDMS PE 40 changed with time when exposed to simulated sunlight (100 MW cm-2). f) The optical microscope image of worn PE, g) healed PE after 12 hours of simulated sunlight irradiation. h) The reflection spectrum of original, worn and repaired Fe3O4 @ C / PDMS PE.
Highlights summary
All in all, by assembling Fe3O4 @ CNP and amino terminated PDMS polymer, we have obtained PE with bright and angle independent structure color, wide spectral response and force induced color. The isotropic and short-range ordered Fe3O4 @ CNP embedded in PE has wide light absorption and high reflectivity, thus obtaining bright and angle independent structural colors. In addition, due to the dynamic and reversible interaction between Fe3O4 @ CNP and polymer chains, and the photothermal properties of Fe3O4 @ CNP, PES can quickly repair cuts and scratches under laser and sunlight. PE with bright color and wide spectrum response can be used in visual sensor, color coating, etc.