Measurement of Viscoelastic Characteristics of Interfacial Layers on Liquid Surfaces Using New Experimental Equipment

Resumo

The viscoelastic characteristics (frequency dependences of the components of the two-dimensional complex dynamic modulus) of interfacial layers formed by polymer solutions on liquid surfaces are measured using a newly-designed instrument. The operation of the instrument is based on the use of a Langmuir trough and a new fast-response system for precise measurement of forces in a surface plane at Boussinesq numbers smaller than ten. Examples are presented to illustrate the abilities of the instrument: the measurement of dilatational dynamic elasticity moduli, the determination of the kinetic parameters of polymer solution spreading at interfaces, and the measurement of the moduli for layers of polymer solutions with different concentrations on solvent surfaces in compression–expansion cycles.