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Rapid Prototyping for Soft‐Matter Electronics
Author(s) -
Lu Tong,
Finkenauer Lauren,
Wissman James,
Majidi Carmel
Publication year - 2014
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201303732
Subject(s) - materials science , laser , electrical conductor , optoelectronics , flexible electronics , elastomer , photolithography , nanotechnology , fabrication , soft lithography , flexible display , microcontact printing , soft matter , composite material , layer (electronics) , optics , thin film transistor , medicine , physics , alternative medicine , pathology , chemistry , colloid
A series of rapid and inexpensive methods to produce elastically soft sensors and circuits in minutes using a CO 2 laser (10.6 μm wavelength) are introduced. These soft‐matter electronics are composed of laser‐patterned films of conductive poly(dimethylsiloxane) (cPDMS) and liquid‐phase gallium–indium (GaIn) alloy embedded in a thin sheet of soft silicone elastomer. Direct laser patterning eliminates the need for photolithography, replica molding, and customized inkjet or microcontact (μCP) printing, and allows conductive traces of cPDMS and liquid GaIn to be rapidly integrated into a single soft‐matter circuit. The versatility of this fabrication method is demonstrated by the production of a variety of electrically functional soft‐matter sensors and circuit elements that contain features with >150 μm planar dimensions. It is postulate that in the case of GaIn alloy patterning occurs when the recoil force of the escaping vapor exceeds the liquid's surface tension. This mechanism exploits the unique “moldability” of liquid GaIn alloy, which forms a surface oxide of Ga 2 O 3 that allows the patterned film to maintain its shape.