Chemical and nanomechanical properties of plasma-polymerized acetylene on titanium and silicon

Deposited PP acetylene films were predominantly carbon (≈87%). Oxygen, the other main constituent (≈13%), was present in the form of C-O and CO functional groups. For both substrates, PP films deposited at lower power exhibited higher hardness and reduced modulus than films deposited at higher power. At two different power levels, PP films deposited on silicon wafers exhibited higher hardness and reduced modulus values than PP films deposited on polished Ti-6Al-4V. Also, film deposition occurred at a faster rate on Ti-6Al-4V. Overall, thinner films exhibited higher hardness and a greater reduced Young's modulus compared to thicker films. For the samples tested, PP films of higher hardness yielded higher critical loads at debond (thickness normalized) in nanoscratch tests.