Engineers at the University of California (UC) Davis have invented a so-called nanoglue that could be used in microchip fabrication.
Conventional glues form a thick layer between two surfaces. Prof Tingrui Pan’s nanoglue, which conducts heat and can be printed, or applied in patterns, forms a layer the thickness of only a few molecules.
According to a statement, the nanoglue is based on a transparent, flexible material called polydimethylsiloxane (PDMS), which, when peeled off a smooth surface, usually leaves behind an ultra-thin, sticky residue that researchers had mostly regarded as a nuisance.
Pan and his colleagues realised that this residue could instead be used as glue. They enhanced its bonding properties by treating the residue surface with oxygen.
Developed with support from the US National Science Foundation, the nanoglue could be used to stick silicon wafers into a stack to make new types of multi-layered computer chips.
Pan, professor of biomedical engineering, said he thinks it could also be used for home applications, for example as double-sided tape or for sticking objects to tiles. The glue only works on smooth surfaces and can be removed with heat treatment.
Pan and his fellow researchers have filed a provisional patent and the journal Advanced Materials published a paper on the work in December 2011.
In separate news, PDMS has been employed at UC Davis in the creation of a transparent pressure sensor. Designed for medical applications, the flexible, transparent pressure sensor is said to rely on a drop of liquid that goes in a flexible sandwich of PDMS.
The sensor acts as a variable electrical capacitor. When the sensor is pressed down, the sensing droplet is squeezed over conductive electrodes, increasing its capacitance.