Deformation behavior of polyurethane treated in argon plasma: impact of surface and subsurface properties

Abstract Separation into surface and subsurface is important when studying complex macromolecular compounds. Investigation of surface-modified materials under application of external load is another challenge. Polyurethane is a phase-separated polymer. It internal structure (stiff fibrils percolating the softer matrix) is covered by a soft nanolayer. Treatment in argon plasma leads to gradual etching and altering the surface and subsurface structures. In first 60 s of the treatment the outer soft layer decreases from 6 to 2 nm becoming stiffer; fibrilar structures are destroyed. After 120 s of the treatment the stiffness and thickness of the coating reaches equilibrium. Cracks were observed in the uniaxial stretched state on the surfaces after treatment