Tuning Thin Film Thickness and Porosity with Layer‐by‐Layer Submicronic Particles Assembly

Abstract Porous NiO films were prepared using Layer‐by‐Layer assembly of submicronic β‐Ni(OH)₂ nanoplatelets and size‐controlled poly(methyl methacrylate) (PMMA) particles. β‐Ni(OH)₂/PMMA thin films were elaborated using different PMMA particle sizes and concentrations. The elaborated films were then heated at a temperature of 325 °C in air for one hour to form porous NiO films by calcining β‐Ni(OH)₂ nanoplatelets. PMMA polymeric particles were also calcined during this process, leading to film porosity. Thermal treatment experiments clearly showed a relationship between PMMA particle size and film properties i. e., porosity and thickness. NiO films exhibited huge pores, around 1 μm, and matter loss after calcination when PMMA particles with a diameter of 190±43 nm were employed. Partial collapsing of the films was also denoted. Experiments were then carried out by decreasing PMMA particle size (100±19 nm) leading to cohesive NiO films. Finally, the specific surface area (SSA) of the NiO films prepared with PMMA particles of 100 nm was determined by adsorption‐desorption of nitrogen gas using the BET (Brunauer–Emmet–Teller) method. This showed an increase in SSA with PMMA particle concentration.