Durable 3D-printed molecular solar thermal fabrics with arylazopyrazole photoswitches for solar energy storage in personal thermal management

Abstract

Effective solar energy harvesting offers vast potential to replace traditional fossil fuels globally. Capturing solar energy efficiently and retrieving energy as heat on demand via molecular solar thermal (MOST) materials, are promising prospects for personal thermal management (PTM). Although many MOST systems offer extended energy storage capabilities, they still face several limitations. These include dependence on specific solvents, low heat output during discharge, limited energy density, poor mechanical durability, and potential leakage issues. To address these issues, herein, we rationally design a novel flexible MOST based woven Kevlar fabric (WKF) for PTM using arylazopyraloze nanocapsule containing a UV-filter shell as MOST and Pd@CoBiO2 nanoflakes grown WKF through 3-D printing technique. This MOST-based WKF fabric integrates arylazopyraloze nanocapsule and Pd@CoBiO2 nanoflakes, facilitating excellent co-capturing solar and phase-change energy. The fabric demonstrates excellent photo-charging and photo-discharging (97% photoconversion), long-term storage (98 days), a high thermal energy storage of 151 Jg(-1), and good capacity of releasing high-temperature heat (46-48 degrees C) at room temperature. Additionally, it remains highly flexible without compromising energy storage performance after 3000 bending cycles, 80 cycles of repeated washing, and 10 h of soaking and high tensile strength (77.1% higher than bare WKF). The fabric can passively reflect radiative heating (96%) while actively capturing the solar energy. The surface temperature of human skin (T-HS) covered by the MOST-WKF fabric can be heated up to similar to 38 degrees C. Additionally, incorporating thermochromic along with photochromic properties facilitates surveilling both comfortable T-HS and energy storage enthalpy. The robust WKF-MOST fabric with high energy-storage performance enables on-demand thermal therapy as an effective PTM.