Damping of cylindrical propagating capillary waves on monolayer-covered surfaces

Abstract

Cylindrical propagating capillary waves are generated by an electrical "point source" and detected with a reflected laser beam. The surface properties of monolayers of soluble (Triton X-100) and insoluble (n-dodecyl p-toluenesulfonate) surfactant solutions were investigated through both propagating plane and cylindrical capillary waves. We found that the values of measured damping coefficients and wavelengths of plane waves are equal to those of cylindrical waves. Computed values of the surface properties, elastic modulus t and surface pressure n, for both waves are obtained and found to be identical. Our results show that even though plane and cylindrical transverse waves possess different geometries, they can be used to obtain surface dilational properties accurately. Also, the dispersion equation for propagating cylindrical waves is explicitly derived.

Determination of Surface Dilational Viscosity Using the Oscillating Bubble Method

“…A review of the problem is given in (10). Wave experiments as well as bubble experiments exhibit a large difference between the calculated and measured values of the surface dilational modulus for faster deformations (11,12,36,37). Therefore, modification of the standard assumption is required.…”

Capillary Wave Damping in Heterogeneous Monolayers

“…This phase transition region extends from very low densities up to a molecular number density N of approximately 0. 8 In this region the monolayer is inhomogeneous. Instead of having uniform density, the monolayer displays a coexistence of the very low-density gas phase and the higherdensity LE phase.…”

Electrocapillary Wave Studies of Oligomeric Ethers: Poly(dimethylsiloxane) and Poly(ethylene glycol)

“…Since we are using real viscous liquids, the wave motion we encounter is always accompanied by dissipation of mechanical energy into heat. If we take into consideration this energy dissipation, then we obtain the wave profile ,, as where β is the spatial-damping constant. Hence the phase difference k o r and wave-damping coefficient are proportional to r and ln[ r 1/2 Ψ( r , t )], respectively.…”