Promoting Heat Dissipation via a Recyclable and Self-Hygroscopic Hydrogel Membrane

Efficient heat dissipation is crucial for the performance and longevity of compact electronic devices, which face significant thermal management challenges. This study introduces a reusable and self-hygroscopic heat dissipation hydrogel using poly(vinyl alcohol) (PVA) and soluble acrylic resins (AR) as the matrix, lithium chloride (LiCl) as the hygroscopic component, and borax and aluminum ions (Al3+) as cross-linking agents. The dynamic covalent cross-linking and physical cross-linking provide enhanced recyclability and mechanical strength, allowing the hydrogel to maintain excellent performance through repeated heat dissipation cycles. The influence of Li+ concentration on the hydrogel’s hygroscopic properties was evaluated, revealing that at 10.0 mol/L Li+, nearly 100% of the water was reabsorbed within 6 h at 20.0 °C. The hydrogel demonstrated superior self-hygroscopic properties and maintained long-term functionality across multiple cycles. The hydrogel effectively reduced surface temperatures of heat sources by up to 20 °C compared with commercial heat fins. The reversible cross-linking mechanism enables the hydrogel to undergo bond breakage and reformation, facilitating recyclability and extending its practical lifespan. This innovative hydrogel presents a promising solution for advancing thermal management in electronic devices and contributes to global sustainable development.