Measurement of forces due to structure in hydrocarbon liquids

摘要: Direct measurements of the force between two molecularly smooth mica sheets immersed in cyclohexane show not a monotonic van der Waals attraction, but an oscillatory function distance, where spacing successive minima corresponds to molecular diameter cyclohexane. As surface separation increases oscillations become less pronounced, and beyond 5 nm (typically seven or eight oscillations) they are no longer detected. These results accord with theoretical ideas on structural forces resulting from inhomogeneous arrangement molecules liquid near solid surface. In n-octane law does same pronounced oscillations, except at very small separations repulsive barriers found. attributed difficulty removing last layers adsorbed surfaces, reduce mice-mica adhesion significantly. Small amounts water hydrocarbon liquids condense form bridge surfaces separations, causing strong them. Some implications these for stability colloids organic media discussed.