(85h) PTF Young Professional SABIC Award Lecture

Authors: 
Teleki, A., Particle Technology Laboratory, ETH Zurich
Flame Synthesis and Coating of Nanostructured Particles in One Step

Surface properties of inorganic or organic nanostructured particles often have to be modified to meet specific needs in final applications. This is accomplished by hermetically depositing shells and/or attaching functional groups onto the core particles. Here, an aerosol reactor has been developed that enables in-­situ coating of flame-­made particles with nanothin SiO2 films. This process is continuous and scalable and serves as a tool to produce particles of increased functionality at limited additional cost. For example, when a SiO2 coating is applied on UV-­absorbing flame-­made TiO2 nanoparticles, their photocatalytic activity is minimized rendering such particles suitable for sunscreens or as nanofiller materials. Silica encapsulation of core nanoparticles offers several advantages, for example it can reduce toxicity of plasmonic Ag nanoparticles, minimize magnetic nanoparticle interactions and reduce particle agglomeration in aqueous solutions. Furthermore, this gas-­phase process is not only limited to silica coatings, but is also further extended for the synthesis of nanoparticles that are surface functionalized with organic groups rendering them hydrophobic. This one-­step SiO2 coating process is also utilized for engineering magnetic nanostructured particles for biomedical applications. Superparamagnetic Fe2O3 nanoparticles or even hybrid Janus­â?like plasmonic­â?magnetic nanoparticles are encapsulated with nanothin, hermetic silica shells that play a decisive role on their final performance. Finally, results of such stimuli­â?responsive nanostructures in a multiscale drug delivery system will be shown where the triggered drug release is achieved by the application of an alternate magnetic field.