Facile fabrication of free-standing colloidal-crystal films by interfacial self-assembly

This paper reports a rapid and facile method of preparing free-standing colloidal crystals from monodisperse charged polystyrene (PS) microspheres. Mixed solvents (ethanol/water) were used as the dispersion medium in the self-assembly process of colloidal crystals. By a simple “floating self-assembly” method, PS microspheres floated on the surface of liquid and self-assembled into large area of three-dimensional (3D) ordered colloidal crystals within 15 min. Then epichlorohydrin was added in as a cross-linking agent to strengthen the colloidal-crystal film. After cross-linking reactions between the microspheres, the obtained colloidal-crystal film was free-standing and could be easily transferred to other substrates. Using tetrabutyl titanate as a titania precursor, 3D porous TiO2 materials with rodlike skeletal structure were fabricated from the prepared free-standing colloidal crystal. This work provides a facile method to fabricate free-standing colloidal-crystal film, which can be used as an ideal template for the preparation of porous materials.

Optical photographs of colloidal multi-layers from PS microspheres of different size: (a) 140 nm, (b) 216 nm, and (c) 282 nm. (d and e) show the free-standing colloidal films prepared from 158 nm microspheres.Figure optionsDownload high-quality image (50 K)Download as PowerPoint slideResearch highlights
► Colloidal crystals are fabricated via “floating self-assembly” method within 15 min.
► Free-standing colloidal-crystal film is obtained using epichlorohydrin as cross-linking agent.
► Free-standing colloidal crystals could be used as ideal templates for 3DOM materials.