Gold squeezed into micro-Velcro

February 8, 2013
Gold squeezed into micro-Velcro
SEM micrographs showing a variety of Au microwire morphologies depending on the overall Au content: a) Short and straight wires appear at 42 at.% Au. b) With increasing Au content to 44 at.% the wires become longer and start bending. c) They achieve a maximum length and a hook-like shape at 48 at.% Au. d) False-color picture generated from elemental composition maps for 46 at.% Au (Au: yellow, W: blue).

Researchers at Ruhr University have used self-assembling techniques to produce gold microwires that have suitable properties for micro-Velcro. The research is published today in Science and Technology of Advanced Materials.

Velcro consists of one surface with loops, and another with hooks that latch onto the loops, joining opposing surfaces strongly. A miniaturised version of Velcro could be used in micro- and nanotechnology, but to form the surfaces, microwires are needed with properties that provide strength and durability.

Several different approaches have been used to construct 'micro-Velcro', but the most promising are those that use self-assembling or self-organising techniques, where microwires are 'squeezed' from a composite material by compression. Researchers at Ruhr University Bochum, Germany, have used this technique to produce gold microwires that have suitable properties for micro-Velcro.

The scientists created of containing gold and tungsten metal. These were then heated to very , causing the tungsten to react with oxygen and form . This increased the volume of the tungsten and caused compression within the composite, 'squeezing' the softer gold out as 'whiskers'.

Different ratios of gold to tungsten were tried in the original composite, and these were heated to different temperatures and for different times to find the optimal conditions. The best result produced gold microwires approximately 35 micrometres long – similar to the width of a human hair – and 2 micrometres in diameter.

The resulting gold microwires have larger diameters than indium metal microwires that had previously been made using a similar technique, making them more suitable for micro Velcro. The results demonstrate that this new approach is a feasible one for producing the microwires that could be used to make micro-.

This research was published in the journal, Science and Technology of .

Explore further: Speedier flexible electronics possible with new fabrication process

More information: Sven Hamann et al 2013 Sci. Technol. Adv. Mater. 14 015003 doi:10.1088/1468-6996/14/1/015003

Related Stories

Microfabrication: The light approach

March 4, 2011

Materials that conduct electricity but which are also transparent to light are important for electronic displays, cameras and solar cells. The industry’s standard material for these applications is indium tin oxide (ITO), ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.