Cyclodextrin directed self-assembly of TiO2 nanoparticles

In this paper we study the self-assembly of TiO2 nanoparticles with cyclodextrin molecules into a self-supporting fiber network. We observe the networkʹs macroscopic growth and evolving microstructure as a function of time and relate these to the chemical changes of the solution and the composition of the growing network. From this data we elucidate the steps of the self-assembly process. The TiO2 nanoparticles initiate a photocatalytic reaction that results in a ring breaking and dehydration of the cyclodextrin molecules in solution. This dehydration exposes the hydrophobic regions of the cyclodextrin molecule to the water solution, supplying the force that drives self-assembly. This same hydrophobic force also leads to branch and junction formation between fibers that ultimately build up the self-supporting network structure.