SURFACE LASER-LIGHT SCATTERING STUDIES OF THE AIR POLY(N-VINYL-2-PYRROLIDONE)-WATER SOLUTION INTERFACE/

An experimental study of poly(N-vinyl-2-pyrrolidone) (PVP) in water so lution has been carried out by using the surface laser light scatterin g (SLLS) technique. The concentration dependence data of the peak freq uency and linewidth are obtained from the SLLS spectra of the PVP/wate r solutions with two PVP molecular weights over a wide concentration r ange varying from the dilute to semidilute regime. The equilibrium sur face tension of the solution is also measured as a function of polymer concentration and molecular weight. In the dilute solution, the peak frequency and surface tension show only a small decrease with increasi ng concentration. However, in the semidilute concentration regime, the surface tension and the frequency shift decrease rapidly with increas ing concentration, accompanied by the dramatic increase in the spectra l linewidth. The surface tension, SLLS spectral peak frequency and lin ewidth show an important molecular weight dependence. Over the entire concentration range investigated, the SLLS data of the PVP/water solut ions do not show evidence of the capillary to Rayleigh wave evolution. (C) 1996 American Institute of Physics.