SAM assisted nickel-boron electroless metallization of PDMS

All-wet metallization of polydimethylsiloxae (PDMS) was carried out through Nickel-phosphorous-boron (NiPB) electroless deposition. Self-assembled monolayers (SAM) of n-(2-aminoethyl) 3-aminopropyl-trimethoxysilane (AEAPTMS) was used to improve the metal thin film adhesion. PDMS surface modification was achieved by sodium hydroxide (1M) immersion followed by corona treatment. Surface roughness changes were examined by atomic force microscopy (AFM) before and after each step of surface modification, silanization and metallization. Glow discharge optical emission spectroscopy (GDOES) confirmed the presence of the deposited layers and activated interface. Scanning electron microscopy (SEM) observations of PDMS/NiPB interface indicated no detachment of NiPB. Samples with three lines of NiPB on PDMS (acting as counter, reference and working electrodes) were prepared for applying as an ethanol sensor. Surface area of the working electrode was 6×6mm². A linear range up to 600ppm with 6.9 μA.ppm^-1.cm^-2sensitivity was achieved for the sensor. Lower detection limit and the response time was 20ppm and 10s.