Journal of Adhesion, Vol.84, No.3, 231-239, 2008
Stretchable gold tracks on flat polydimethylsiloxane (PDMS) rubber substrate
A process to fabricate stretchable gold tracks on silicone rubber substrates is studied by XPS, static water contact angle measurement, AFM, and SEM. The process involves several steps: removing uncured oligomers by hexane Soxhlet extraction; pre-stretching the substrate; activating the strained silicone surface by an oxygen plasma treatment; coating the strained substrate with 5nm titanium and 80nm gold layers; and finally releasing the sample. The plasma treatment creates a thin brittle silica-like layer that temporarily increases the substrate's surface energy. Indeed, the plasma treatment is followed by a hydrophobic recovery. As a consequence, the delay between plasma treatment and metal deposition has to be reduced as much as possible. The silica-like layer can be nicely observed after release. The entire process allows us to obtain stretchable metallized samples that remain conductive even after an excessive deformation leading to electrical failure.
Keywords:buckling;hydrophobic recovery;metallization;plasmatreatment;polydimethylsiloxane ( PDMS);silica-like layer;stretchable conductor