Parameters Influencing the Templated Growth of Colloidal Crystals on Chemically Patterned Surfaces

Abstract

The influence of various experimental parameters on the vertical deposition and structure formation of colloidal crystals on chemically patterned surfaces, with hydrophilic and hydrophobic areas, was investigated. The pattern dimensions range from about 4 to 400 microm, which is much larger than the individual particle size (255 nm), to control the microscopic crystal shape rather than influencing the crystal lattice geometry (as achieved in colloidal epitaxy). The deposition resolution and selectivity were tested by varying the particle concentration in the suspension, the substrate withdrawing speed, pattern size and orientation, and wetting contrast between the hydrophilic and hydrophobic regions. The evolution of colloidal crystal thickness with respect to the pattern dimensions and deposition parameters was further studied. Our results show that the pattern size has a rather strong influence on the deposited number of colloid layers and on the crystal quality. Better results are obtained when the lines of a stripe pattern are oriented parallel to the withdrawing direction rather than perpendicular. The deposition resolution (defined as the minimum feature size on which particles can be deposited) depends on the wetting contrast and increases with lower average hydrophobicity of the substrate.

Design and fabrication of colloidal polymer nanocomposites

“…Jonas et al [47] investigated the parameters influencing the templated growth of colloidal particles on chemically-patterned surfaces by vertical deposition. In this case, silanol groups were used to create hydrophilic surface regions, and fluoroalkysilane monolayers were used to create hydrophobic surface patterns.…”

“…For example, a nonlinear dependence of the film thickness on the colloid concentration and the substrate withdrawal speed was identified for line patterns with widths below 100 µm in Jonas et al's work. [47] Control of this particular deposition behaviour is still based on empiricism and more precise work combined with modelling needs to emerge.…”

High Frequency Acoustics in Colloid-Based Meso- and Nanostructures by Spontaneous Brillouin Light Scattering

“…An interplay of long-range attractive and short-range repulsive forces causes the self-assembly of the colloidal material into a face-centered cubic (f cc) or hexagonally close packed (hcp) crystal . [54,55] In order to control the thickness of such a colloidal crystal -a critical parameter for further use in ensuing applications -the substrate is withdrawn from the dispersion at a certain speed at given environmental parameters such as temperature and humidity. Besides the fabrication of such 'simple' colloidal crystals also more complex systems like binary [56,57] and ternary colloidal crystals [58] were demonstrated.…”

“…By vertical lifting deposition [54] non-transparent films of the colloids with thickness of about 30-50 µm were prepared by M. Retsch. The BLS eigenmode spectra were recorded in transmission geometry at (nonarbitrative, due to strong multiple scattering) scattering angle of 50 • .…”

“…[54] For different experiments, two kinds of monodisperse polystyrene (PS) spheres with diameters of d=307 nm and 360 nm and poly(methylmethacrylate) (PMMA) particles with a diameter of d=327 nm were used for the fabrication of the opals. Additionally, a noncrystalline hybrid film consisting of PS sphere mixture with two different diameters (300 nm and 360 nm) was prepared in the same way.…”