Abstract
The structures of the one-dimenstional alignment of silica nanoparticles and the mechanical properties of their colloidal solutions were investigated. The morphology of the colloidal silica was found to be similar to a "pearl-necklace" structure, which could be formed by adding about 80 wt% of ethanol. The silica nanoparticle solution in one-dimensional alignment showed a weak gel-like behavior whereas the solution with the particles in the dispersion state, which was discretely controlled at lower ethanol concentration, showed a sol-like behavior. The increase in the elastic modulus associated with the change in the particle-dispersion state was highly due to the formation of the worm-like structure connected through Si-O bonding between particles. The attraction force between particles was presumably induced by adding ethanol, reducing the surface charge of the particles.
