The line tension values of n-octane and 1-octene on a hexadecyltrichlorosilane coated silicon wafer, are determined by contact angle measurements at temperatures near a first-order wetting transition $T_w.$ It is shown experimentally that the line tension changes sign as the temperature increases toward $T_w$ in agreement with a number of theoretical predictions. A simple phenomenological model possessing a repulsive barrier at $l_0=5.1\mathrm{}\pm 0.2\mathrm{nm}$ and a scale factor of $B=78\mathrm{}\pm 6$ provides a quantitative description of the experiments.

We present atomic force microscopy observations of the “effective” slippage of various nonpolar and polar liquids on alkylsilane coated glass surfaces. For small contact angle nonpolar liquids, the slip length decreases as one approaches a wetting transition. However, for large contact angle polar liquids it is found that the slip length is primarily influenced by the dipole moment, rather than the wettability of the liquid for the surface, where the slip length decreases with increasing dipole moment.

In this paper we quantitatively compare various electrostatic models, which describe the interaction of a polarized atomic force microscopy tip with a molecularly smooth and grounded substrate, with a large experimental data set collected at many different tip potentials. The model by Hudlet et al. [Eur. Phys. J. B 2, 5 (1998)] provides an excellent description of the experimental data for tip parameters (height H, cone half-angle ${\theta }_0,$ and tip radius $R_0)$ close to their typical values, provided contributions from the cantilever body are included.

We report the results of Rayleigh-scattering experiments in liquid toulene that is subjected to a stationary temperature gradient, but which otherwise is kept in a quiescent state. The measurements were made with temperature gradients up to 224 K/cm and scattering angles down to 0.45°. They probe fluctuations with wavelengths up to 40 μm and demonstrate the presence of long-range fluctuations in a nonequilibrium liquid. The strength of the observed nonequilibrium heat-mode and viscous-mode fluctuations varies with the square of the temperature gradient and with the fourth power of the wavelength of the fluctuations, in agreement with the behavior predicted by fluctuating hydrodynamics.

The behavior of the line tension for $n-\mathrm{octane}$ or 1-octene droplets on a hexadecyltrichlorosilane coated Si wafer, near a first-order wetting transition, qualitatively agrees with the theoretical predictions of Indekeu [Physica (Amsterdam) 183A, 439 (1992)] and the calculations of a number of other groups. A simple phenomenological model possessing a repulsive barrier at $l_0=(5.1\pm 0.2)\mathrm{nm}$ and a horizontal correlation length $\xi =(0.40\pm 0.03)\mu \mathrm{m}$ provides a quantitative description of the experiments.