Dynamics of the layer-by-layer assembly of a poly(acrylic acid)–lanthanide complex colloid and poly(diallyldimethyl ammonium)

Poly(acrylic acid) (PAA) and lanthanide (Ln) ions, such as Ce3+, Eu3+, and Tb3+, were prepared as dispersed complex colloidal particles through three different protocols with rigorous control of the pH value and mixing ratio. The negatively charged PAA–Ln complex particles were layer-by-layer (LbL) assembled with positively charged poly(diallyldimethyl ammonium) (PDDA) to prepare a thin film. The film thickness growth is much quicker than PDDA/PAA film. Due to the incorporation of Ln3+ ions, the film exhibits fluorescence. During LbL assembly, PDDA–PAA association based on electrostatic force and PAA–Ce association based on coordination are in competition, which leads to the LbL assembly of PDDA and PAA–Ln complex colloidal particles being a complicated dynamic process.