Resilient and robust mechanoresponsive polydimethylsiloxane/SiO₂ composites induced by interfacial enhancement

The transition of material transparency induced by mechanical stimulation plays a crucial role in applications such as information encryption, anti-counterfeiting, and smart windows. However, developing a multifunctional composite film that simultaneously possesses high resilience, high sensitivity, low energy consumption, and reusability remains a significant challenge. In this work, homogeneous silica (SiO₂) nanoparticles were modified by a commercially available coupling agent KH570, enabling it to be chemically bonded to the polydimethylsiloxane (PDMS) polymer networks, which enhanced the interfacial interaction and allowed the periodic structure of SiO₂ to return to its original state effectively both before and after stretching. After undergoing 200 cycles of testing, the composite film exhibited low energy dissipation, with its transmittance maintaining high stability within the range of 90-20 %. At -50 °C, the maximum loss factor of the composite film was ∼0.24, indicating that it retained high resilience even at low temperature. The composite film is a promising candidate for smart window, as it can be operated with low energy input solely through mechanical force. Furthermore, we adopted advanced imprinting technology, utilizing selectively designed molds to embed arbitrary encrypted information. By controlling the imprinting duration to 5, 30 and 80 s, we achieved differentiated information displays under the same strain conditions on a single film. Therefore, this work can provide new insights into fields such as smart windows, information encryption, and strain sensing.