Gold squeezed into micro-Velcro

Feb 08, 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: Scientists fabricate defect-free graphene, set record reversible capacity for Co3O4 anode in Li-ion batteries

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

add to favorites email to friend print save as pdf

Related Stories

Microfabrication: The light approach

Mar 04, 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 ...

Recommended for you

Copper shines as flexible conductor

Aug 22, 2014

Bend them, stretch them, twist them, fold them: modern materials that are light, flexible and highly conductive have extraordinary technological potential, whether as artificial skin or electronic paper.

Nanoparticles may aid oil recovery, frack fluid tracking

Aug 22, 2014

Two Colorado State University researchers are examining how nanoparticles move underground, knowledge that could eventually help improve recovery in oil fields and discover where hydraulic fracking chemicals ...

Nanostructure enlightening dendrite-free metal anode

Aug 19, 2014

Graphite anodes have been widely used for lithium ion batteries (LIBs) during the past two decades. The replacement of metallic lithium with graphite enables safe and highly efficient operation of LIBs, however, ...

User comments : 0