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Physicists demonstrate a new device for manipulating and moving tiny objects with light

When you shine a beam of light on your hand, you don’t feel much, except for a little bit of heat generated by the beam. When you shine that same light into a world that is measured on the nano- or micro scale, the light becomes a powerful manipulating tool that you can use to move objects around – trapped securely in the light.

More realistic research needed on substances that enter the environment

Chemical substances and nanomaterials are processed on a massive scale in diverse products, while their risks have not been properly assessed. Time and again synthesised substances have been shown to pollute the environment more than lab tests predicted. This is the warning given by Professor of Ecotoxicology Martina Vijver from Leiden University in her inaugural lecture on 16 November.

Laboratory tests are inadequate, according to Vijver, because they do not imitate a complete ecosystem. In her inaugural lecture she will discuss in greater detail two examples of substances where more realistic research is needed: agricultural toxins and nanoparticles. ‘But the same can be said for many other groups of substances, such as antibiotics, plasticizers and GenX.’

Detecting light in a different dimension

“We did not expect to see such a dramatic improvement just by changing the morphology of the polymer,” said co-corresponding author Mircea Cotlet, a materials scientist in the CFN Soft and Bio Nanomaterials Group.

The scientists believe that there are two explanations behind their observations.

“At a certain polymer concentration, the nanowires have dimensions comparable to the wavelength of light,” said Li. “This size similarity has the effect of increasing light scattering and absorption. In addition, crystallization of P3HT molecules within the nanowires provides more charge carriers to transfer electricity to the layer.”

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