Size, morphology and optical properties of ZnO nanoparticles prepared under the influence of honeycomb-porous poly[(2-hydroxyethylmethacrylate)m-block-poly(N-phenyl maleimide)n] copolymer films

Abstract

The effect of the particles size of ZnO nanoparticles, synthesized into the microstructure of honeycomb-porous block copolymer films (poly[(2-hydroxyethylmethacrylate)m-block-poly(N-phenylmaleimide)n]) with different lengths, on the thermal, morphological and optical properties of the porous-structured films were investigated. The functional nanoparticles (NPs) were synthesized by wet preparation methods involving the porous copolymer films. The presence of the copolymer allows the coordination of Zn2+ precursor with the hydrophilic part of the self-assembled block copolymers resulting in hierarchically-ordered NP arrays. With this approach, the microphase separation inside of the polymer domains was used for the organization of pre-formed NPs in their cavities. The results indicated that the sub-domains formed by hydrophilic moiety represent an additional advantage for the diffusion and formation of ZnO nanoparticles. Absorption spectra of the ZnO NPs showed an excitation band around 300nm, indicating a blue-shift with respect to the ZnO bulk material (at 373nm). The size and the spherical morphology of the prepared ZnO NPs were determined by transmission electron microscopy (TEM). The overall morphology of polymer nanocomposite (ZnO embedded in the block copolymer) was determined by scanning electron microscopy (SEM) and atomic force microscopy (AFM).