Experimental study reveals pH-driven proton transfer optimizes organosilane film assembly on copper, indicating an eco-friendly path for anti-corrosion surface engineering.
Key Points
To elucidate how solution pH regulates interfacial electronic structures and molecular bonding strength through proton-transfer processes at metal-organic interfaces.
Assembled aminopropyltrimethoxysilane corrosion-protection films onto copper substrates across varying solution pH conditions.
Conducted surface characterization and theoretical calculations to evaluate molecular energy gaps, electron transfer, and interfacial coordination.
Films prepared under weakly alkaline conditions (pH 9) demonstrated a low-frequency impedance modulus of 1.77×10^6 Ω·cm2 and an anti-corrosion protection efficiency exceeding 99%.
Alkaline conditions triggered ionization of silanol groups (Si-O-) and enhanced electron transfer, enabling non-protonated amino groups to form strong N-Cu coordination bonds with a binding energy of 131.4 kJ/mol.
Acidic conditions caused amino group protonation (-NH3+), broadening the energy gap and diminishing molecular electron-donating capability, which severely impaired interfacial bonding.