Self-assembly nano-structure of type I collagen adsorbed on Gemini surfactant LB monolayers.

The self-assembly nano-structures of type I collagen adsorbed on anionic Gemini surfactant LB monolayer were observed by using atomic force microscopy (AFM) images. It was found that the adsorption behavior and self-assembly structure of collagen could be controlled by the concentration of the collagen solution, adsorption interval and the properties of substrates. With the increase of the adsorption interval and concentration of collagen, the strands size of collagen changed.

Auto-organized nano-structure of collagen on Gemini surfactant monolayer.

Two kinds of Gemini surfactant monolayer, which showed different hydrophobic property, were selected as adsorption substrates for collagen. The topographic images of collagen were investigated by using an atomic force microscopy (AFM). Their auto-organized nano-structures were influenced by the property of substrate and the process of sample preparation, such as concentration of collagen solution, adsorption time and drying condition.

Three-dimensional centimeter-sized colloidal silica crystals formed by addition of base.

Three-dimensional (3D) centimeter-sized colloidal crystals can be spontaneously formed simply by dropping a NaOH solution (10 mM, approximately 10 microL) into an aqueous dispersion of dilute charged colloidal silica (particle diameter 110 nm, particle volume fraction phi = 0.023, 3-4 mL). The charge number of the silica particle increases with pH.

One-directional crystal growth in charged colloidal silica dispersions driven by diffusion of base.

Aqueous dispersions of charged colloidal silica particles showed a novel one-directional crystal growth by diffusion of a weak base, pyridine. The colloidal crystal consisted of pillar-shaped crystal grains whose height and width were in the order of centimeter and subcentimeter, respectively. The growth process was explainable in terms of (i) the diffusion of pyridine with neutralization reactions between weakly acidic silica surfaces, (ii) charging up of the silica particles, and (iii) the charge-induced crystallization of the dispersions.