Strong Lateral Confinement of Hydrophilic Silica Nanoparticles on Mg‐Al Layered Double Hydroxides Nanoflakes for Enhanced Thermal Properties

ABSTRACT Developing efficient, thermally resistant, and fire‐retardant materials requires innovative approaches to modulate the mean free path of air for thermal transport in insulators. Herein, an inorganic silica NPs@Mg‐Al LDH nanocomposite is designed, which synergizes the lateral interactions of monodisperse, hydrophilic silica nanoparticles (NPs) and layered double hydroxides (LDH) nanoflake lamella structure. Upon heating to 550°C, the nanocomposite composed of LDH and silica with a weight ratio of 1:3 (LDH1Si3) exhibits a remarkably higher thermally stable structure, outperforming its counterparts in terms of their structural rigidity. Advanced characterization techniques, including microscopy (TEM, SEM, and STEM/EDX), spectroscopy, and thermal analysis, reveal that the effective integration of 3D network structures without phase segregation enhances heat transport by utilizing voids, gaps, and holes, resulting in minimal structural loss at high temperatures. The silica NPs serve as the dominant thermally stable active sites, concurrently MgAl‐LDH introduces improved thermal resistance with interfacial Si─O─M (M = Mg, Al) bonding. This work unveils a facile, cost‐effective, and non‐toxic nanomaterial that can be designed as a high‐temperature insulating coating for fabrics.