Bioinspired Dual‐Shielding Molecular Solar Thermal Fibrous Membrane for Enhanced Thermal Retention and Self‐Powered Wearable Sensing

Molecular solar thermal (MOST) materials enable reversible energy storage and release through photoisomerization, offering a promising strategy for wearable thermal management. However, bridging molecular‐scale energy storage and device‐level heat utilization remains challenging, as severe convective and radiative losses under windy conditions substantially degrade the thermal output of MOST systems. Here, a dual‐shielding molecular solar thermal fibrous membrane (DS‐MSTFM) is developed by constructing a columnar‐protrusion fibrous substrate with PDMS/air microcavities and an Ag nanosheet radiation‐shielding layer. The swelling–deswelling strategy enables uniform crystalline azobenzene loading with an areal energy density of 10.4 kJ m −2 , while fibrous confinement suppresses molecular aggregation and achieves a maximum Z‐isomer fraction of 91.95%. Benefiting from synergistic convection and radiation shielding, DS‐MSTFM exhibits a 5.4‐fold prolonged cooling time constant and a 41.6% reduction in total heat transfer coefficient. Under intensified airflow (2.0 m s −1 ), DS‐MSTFM exhibits negligible thermal attenuation, whereas pristine MSTFM suffers severe wind‐induced heat dissipation with a 57% loss of heating capability. Furthermore, DS‐MSTFM enables photothermal warming at −20°C and self‐powered pulse and motion monitoring. This work provides a device‐level strategy for overcoming thermal‐loss limitations in MOST systems and enables multifunctional wearable platforms integrating thermal regulation with self‐powered sensing.