FIGURE 5.

Magnification of the surface-force isotherm between two PLL-g-PEG covered surfaces in pure water. Discrete film-thickness transitions with a step size 125 ± 25 pm (statistics based on 40 isotherms) reveal the presence of long-lived, load-bearing equilibrium structures in the PLL-g-PEG film. Similar film-thickness transitions are also observed in the case where only one surface is decorated with PEG. The transitions are observed in sequences of 6–10 individual transitions, separated by regions of similar extension (≈1–1.5 nm) without clear transitions. The loading speed was held constant at 1 nm/s using a closed feedback loop. For the sake of simplicity, only one error bar is shown, which represents the instrumental precision of this measurement.