The reduced surface energy, , as a function of wall separation, . The squares are the simulation results of Murat and Grest6 for chains of and surface coverage ; the circles, experimental results of Taunton et al. 23 on toluene-solvated polystyrene tethered to mica surfaces; the triangles, the result of DFT theory ; the solid line is the Alexander–DFT prediction. The theory and simulation curves are shifted in the vertical direction by an arbitrary amount so as to match the experiment. In the inset, the unshifted DFT and simulation results are shown along with the (shifted) Alexander–DFT prediction.
The average layer thickness as a function of the cube root of the surface coverage . Chain lengths of , 20, 30, 40, 50, and 100 are shown. In the scaling regime, a linear relationship exists as predicted by scaling theory. In the inset, the slopes of vs are plotted vs. chain length. A linear relation is found—also in agreement with scaling theory. The solid points are the result of DFT calculations while the open points are computer simulation results of Grest et al. 13 The dashed curve is the boundary between the mushroom and scaling regimes.
The surface force as a function of the wall separation. . The symbols are the results of DFT theory. The lines are the Alexander–DFT predictions.
The reduced surface force as a function of reduced layer thickness. All the systems indicated as being in the scaling regime in Fig. 2 are shown. The different chains lengths have been shifted vertically for clarity with, from lowest to highest, , 20, 30, 40, 50, and 100. The lines are the Alexander predictions. In the inset, the unshifted points are shown.
The reduced layer thickness vs. reduced wall separation. The symbols are results of DFT theory have been shifted vertically for clarity with, from lowest to highest, , 20, 30, 40, 50, and 100. The lines are the curve fit reported Eq. (4.2) and is combined with the Alexander surface force expression in the Alexander–DFT predictions of Figs. 1 and 3. In the inset, the unshifted points are shown.
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