Apr 9, 2020
Updated: Apr 17, 2020
Building with nanospheres makes it possible to, step by step, add functionality. The simplest starting point is a sphere made of silica glass, a few hundred nanometer in size, while the end result can be a of a sphere coated with tiny gold spheres or a with nanowires sticking out: then they look like the sphere-shaped Allium flower. By combining spheres and creating a ‘wrinkly’ surface, a bio-inspired surface is possible that has the sticky characteristics of a rose petal, or the water repellent behavior of a Lotus leaf instead.
Color code
Wang describes other powerful combinations. As the spheres can act as photonic crystals, reflecting a specific color of light, they can together form a color ‘watermark’ that can’t be copied. In materials analysis, the technique of surface plasmon resonance (SPR) is often used in combination with gold surfaces: that’s why gold-covered spheres are very interesting. SPR works by shining light on the surface for activitating electrons: locally the reflected light gives information about the substance on top of the gold. Combining SPR with the photonic crystal behavior, may even lead to materials analysis using a simple color scan, where the color shift can be used as an indication of the binded substances, for example for diagnostics.
The flower-like spheres, of which the silica nanowires are connected by gold on top, have special 'wetting' properties: they can be used for manipulating fluids, for example in separating oil and water or as a basic component in microreactors.
3D hierarchical particle assemblies with nanostructure-enabled functionalities
Juan Wang
University of Twente (2020)
DOI: 10.3990/1.9789036549424
Contact information:
Juan Wang
PhD researcher at University of Twente
J.Wang-6@utwente.nl
University of Twente
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