ABSTRACT In recent years, stimulus‐responsive materials, particularly light‐responsive materials, have attracted significant research interest due to their extensive applications in soft robotics, flexible electronics, and so on. However, most reported systems require high photothermal filler contents (>5 wt%) to achieve effective actuation, which often compromises mechanical properties and durability. Herein, we report a visible‐light‐driven composite film with low carbon dots (CDs) content of only ∼1.4 wt%. This composite film features a dual‐layer structure comprising a composite layer composed of proanthocyanidins‐4‐methoxybenzaldehyde (PM), CDs, and polyvinyl alcohol (PVA), and a polydimethylsiloxane (PDMS) layer. The resulting film responds quickly to visible light irradiation because of the synergistic photothermal effect of CDs and PM, thereby causing an uneven distribution of stress between the two layers due to their mismatched coefficients of thermal expansion. Interestingly, this film exhibits excellent mechanical performance, with a high Young's modulus of 920 MPa and a tensile strength of 37.8 MPa, while maintaining robust durability over 1000 cycles. As proof‐of‐concept applications, smart windows and smart clothing based on the PM/CDs/PVA/PDMS film are developed to enable autonomous light regulation and breathable management. We believe this strategy, based on low photothermal material content, can provide new insights for the development of stimulus‐responsive materials.
Zhan et al. (Mon,) studied this question.