Photocontrolled dispersibility of colloidal silica by surface adsorption of a calix[4]resorcinarene having azobenzene groups
- 1 January 1997
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry
- Vol. 7 (4) , 641-645
- https://doi.org/10.1039/a607145g
Abstract
A novel calix[4]resorcinarene (4-AzCRA) having fourp-butylazobenzene residues attached to the upper rim of the cyclic framework has been prepared and subjected to adsorption on the surface of colloidal silica particles. The trans–cis photoisomerization of 4-AzCRA went almost to completion without being affected by the adsorption on the surface. UV irradiation of a homogeneous dispersion of surface-modified silica particles in cyclohexane enhanced the sedimentation owing to the increase in surface polarity, leading to the formation of porous precipitates. Subsequent visible light irradiation regenerated a dispersed state, displaying photocontrol of the reversible alternation between dispersed and aggregated states of the silica particles.Keywords
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