In the recent years, the art of synthesising and tailoring nanoparticles with distinct properties has attracted tremendous interest and has been explored very well. The next step further is to consider these particles as nano-building blocks which shall be combined bottom-up, to form again particles, but now complex, nanostructured particles. The aim is to achieve novel functional particles with interactive properties that can only be obtained from the smart assembly of nano-building blocks to combined entities. In this talk, two examples of such complex particle entities using nano iron oxides with superparamagnetic properties as building blocks will be shown. The first example is about the formation of hollow microballoons derived from superparamagnetic iron oxide nanoparticles with silica patches. Using patchy iron oxide nanoparticles is the key towards being able to create hollow micron sized entities which evolve from a lifelike Pickering-emulsion process. Ultimately, it is possible to obtain a magnetically steerable particle system with a density of less than 0.2 g/cm3. The second example is about a smart optical composite material with isotropic and anisotropic optical properties by combination of luminescence and high reflectivity which enables switching between both depending on an applied wavelength of light. The composite is formed as anisotropic core/shell particles by coating superparamagnetic iron oxide-silica microrods with a layer of the luminescent metal-organic framework and can be rotated by an external magnet. The integration and control of light emission modes within a homogeneous particle dispersion marks a new type of smart optical material, addressing fundamentally new directions for research on switchable multifunctional materials.

Complex superparamagnetic particle architectures: Obtaining novel properties by controlled assembly and combination of nano-building-blocks to nanostructured entities

253rd National Meeting (2017)

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