Ion-exchange reactions and photothermal patterning of monolayer assembled polyacrylate-layered double hydroxide nanocomposites on solid substrates

Hydrotalcite-like, layered double hydroxide [Mg₄Al ₂(OH)₁₂]CO₃·nH₂O (LDH) nanocrystals immobilized on solid substrates were incorporated with anionic polymers as host matrixes in the intercalation of polyacrylates to produce polymer-inorganic hybrid nanocomposites films on the substrates. The novel functional hybrid films were prepared through a direct ion-exchange reaction of poly(acrylic acid) (PAA) macromolecules into the immobilized LDH in binary solvent systems at 120°C. SEM images reveal that designed solvent mixing such as alcohol and toluene prevents dissolution of LDH compounds, preserving the high crystallinity of PAA-LDH materials after anion-exchange reaction. X-ray diffraction spectra for polymer/LDH nanohybrids materials gave interlayer spacing of 22 Å regardless to the starting materials with different molecular weights, suggesting a molecular modeling of polymer species in gallery space of LDH. The UV-light decomposition of PAA-LDH composite nanocrystals on Si changes their thickness, restoring their pristine basal spacings. This study describes tailoring of PAA-LDH composite systems on the solid substrates and their applications in light-induced patterning.