Absolute local conformation of poly(methyl methacrylate) chains adsorbed on a quartz surface.

This article focuses on elucidating the absolute local conformation of poly(methyl methacrylate) (PMMA) chains at the buried interface with a quartz surface using phase-sensitive sum frequency generation (ps-SFG) vibrational spectroscopy combined with all-atomistic molecular dynamics (MD) simulations. The study demonstrates that after thermal annealing, the ester methyl (OCH3) groups of PMMA predominantly orient toward the quartz interface within a depth of less than 1 nm, breaking inversion symmetry in the orientational distribution. MD simulations reveal two distinct local conformations at the interface, with the energetically favored conformation involving hydrogen bonding between carbonyl groups of PMMA and hydroxyl groups on quartz. These findings provide molecular-level insight into polymer chain behavior at polymer/inorganic solid interfaces, which is important for understanding and improving the performance of polymer nanocomposites and thin-film devices.