Regularity maintenance property of multilayered assemblies of organic, inorganic, and their alternating nanoparticle layers under heating

The regularity maintenance properties of a multi-layered assembly of a polystyrene nanosphere layer, a stearate-modified Fe3O4 nanoparticle layer, and their alternating nanoparticle layers on heating were compared. The purpose is to clarify the heating resistance among the environmental resistance of hard and soft nanoparticle alternating layered structures with excellent mechanical properties. The polystyrene spread at the air/water interface formed a single-particle layer with a uniform height, creating a highly ordered layer structure. Inorganic nanoparticles whose outermost layer surface was modified with organic molecular chains also formed a single-particle layer on the water surface, and the regularity of their layered organization was ensured. Furthermore, the regularity of the alternating multilayers of polystyrene/Fe3O4 nanoparticles with high mechanical resistance that imitate the nacre was not inferior to the regularity of every single component multi-particle layers. When the periodicity of the three types of particle-layered structures was evaluated under high-temperature conditions, it was found that the structures could be maintained up to 80 °C. From paracrystal analysis, it was found that the degree of order reduction was negligible in both the polystyrene nanoparticle layer and the polystyrene/stearate-modified Fe3O4 alternating layers, even at 80 °C. The organo-modified inorganic nanoparticle layers showed outstanding heat resistance, maintaining layered regularity even at 150 °C. This result was predicted to be owing to the effect of two-dimensional crystals formed between the layers of organo-modified chains. [Display omitted] •The hard/soft alternating nanoparticle layers were maintained order up to 80 °C.•Multiparticle layers of polystyrene as soft layer component, also maintained order up to 80 °C.•Multilayers of organo-Fe3O4 as hard layer component, maintained order at 100 °C and above.•Regularity of Fe3O4 layers under heating is supported by two-dimensional crystals between layers.•Two-dimensional crystal between layers were formed by modified chains on Fe3O4 surface.