Alignment of Mesostructured Silica on a Langmuir-Blodgett Film

Abstract

Biomimetic control over the hierarchical structure of inorganic materialsusing ordered organic surfaces can give rise to elongation and uniaxial alignment, shown here for mesostructured silica particles (see Figure). The alignment direction was normal to the axis of the polymer chains of the Langmuir–Blodgett film, which indicates that an alignment mechanism different from the rubbing method dominates this alignment.

Film to Fiber Transformation of Preferentially Aligned Mesostructured Silica

“…The SEM images of the peeled fibrous mesostructured silica synthesized under the condition of HCl / H 2 O = 3 : 100 are shown in Figure 4. [42] The large aspect ratio and the smooth surface morphology of the fibrous mesostructured silica indicates the existence of the preferential growing direction on the rubbing-treated polyimide surface. 4A).…”

Lithographically Formed Fine Wavy Surface Morphology for Universal Alignment Control of Mesochannels in Mesostructured Silica Films

“…The former is formed from the air interface (arrow 1 in Figure ) and the latter is formed from the substrate surface (arrow 2 in Figure ). In our previous study, alignment control over the whole thickness has been achieved on a substrate with anisotropic polyimide coatings using alkyl-PEO surfactants. − Strong surface interactions between the anisotropic polyimide chains and the surfactant molecules should prompt the formation of an aligned liquid crystal phase, which suppresses the formation of a top layer with random alignment from the air interface. In the present study, the alignment control is a result of minimization of the elastic energy and the interactions between the substrate surface and the P123 molecules should be weak.…”

“…Various substrates with surface anisotropy have been proposed for the preparation of mesostructured films with macroscopic structural anisotropy. − However, none of them reported so far are universal; some limit the available surfactants and some lead to the inevitable formation of multidomain structures. For example, substrates with anisotropic polymer coatings − provide highly anisotropic structures over a wide area through anisotropic interactions with the surfactant molecules at the surface. However, the available surfactants are limited to those with a long alkyl chain for such substrates, which consequently sets the upper limit of the structural periodicity.…”