FIGURE 10.

Lateral proportionality coefficient μ as a function of lateral tip displacement rate (from 3.16 to 100 μm/s) in NaCl solutions, pH ∼5.6, calculated as the least-squares estimator ±95% confidence interval from eight series of applied normal forces at the same IS and lateral displacement rate. The μ varied significantly with displacement rate at 0.1 M and 1.0 M IS (one-way ANOVA, p < 0.0001); no significant effect of rate was found at 0.001 M. The value μ was found to vary significantly with IS and rate (two-way ANOVA test, followed by Tukey-Kramer post-hoc multicomparison test, p < 0.0001).