However it is most often ignored that the adhesive force is dependent only on the particle radius ( for wettable, spherical particles, at least ) and therefore independent of the relative vapor pressure or humidity, within very wide limits.
12.
Two thin films made of perfluorinated lubricants ( PFPE ) with different chemical composition were found to have opposite behaviors in humid environment : hydrophobicity increases the adhesive force and decreases lubrication of films with nonpolar end groups; instead, hydrophilicity has the opposite effects with polar end groups.
13.
The setae of a typical mature gecko would be capable of supporting a weight of : each spatula can exert an adhesive force of 5 to 25 nN . The exact value of the adhesion force of a spatula varies with the surface energy of the substrate to which it adheres.
14.
The results were tested with a scanning probe microscope, and it showed that the minimum force per unit area as 1.6?.5?0 " 2 nN / nm 2, which is far larger than the figure the team estimated for the typical adhesive force of a gecko s setae, which was 10 " 4 nN / nm 2.
15.
The rapid change in shape of the boot is designed to break the adhesive force between the ice and the rubber, and allow the ice to be carried away by the relative wind flowing past the aircraft . However, the ice must be carried away cleanly from the trailing portions of the surface, or it could re-freeze behind the protected area.
