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Reversible Cluster Formation of Colloidal Nanospheres by Interparticle Photodimerization
Author(s) -
Yuan X.,
Fischer K.,
Schärtl W.
Publication year - 2004
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200305084
Subject(s) - materials science , nanoparticle , colloid , irradiation , monomer , aqueous solution , photochemistry , chemical engineering , light scattering , molecule , dynamic light scattering , polymer , cluster (spacecraft) , wavelength , nanotechnology , scattering , organic chemistry , optics , chemistry , optoelectronics , composite material , physics , nuclear physics , computer science , engineering , programming language
Crosslinked spherical nanoparticles based on trimethoxysilane monomers have been prepared by polycondensation in aqueous emulsion. These particles have been labeled chemically at their surface region with two different types of organic dye molecules (cinnamate, coumarin), which both are well known for their ability to undergo a reversible photodimerization if irradiated with light of a suitable wavelength. Upon irradiation of dilute solutions of these nanoparticles with UV light, the photodimerization of labels belonging to different colloidal nanoparticles caused the formation of large colloidal clusters consisting of chemically bound individual nanospheres. This process has been quantitatively investigated using light scattering and atomic force microscopy. Importantly, utilizing the reversibility of the photoreaction, the clusters could be broken up by irradiation of the sample with UV light of shorter wavelengths than the light used for their formation