Surface viscoelasticity

Petera, J. and Nassehi, V., 1996. Finite element modelling of free surface viscoelastic flows with particular application to rubber mixing. Int. J. Numer. Methods Fluids 23, 1117-1132. 

Protein-polysaccharide complexation affects the surface viscoelastic properties of the protein interfacial layer. Surface shear rheology is especially sensitive to the strength of the interfacial protein-polysaccharide interactions. Experimental data on BSA+ dextran sulfate (Dickinson and Galazka, 1992), asi-casein + high-methoxy pectin (Dickinson et al., 1998), p-lactoglobulin + low-methoxy pectin (Ganzevles et al., 2006), and p-lactoglobulin + acacia gum (Schmitt et al., 2005) have all demon-... 

There have now been attempts to determine rheological properties on the nanoscale. The nano-rheological properties (surface viscoelasticity) of emulsion droplets have been estimated through modelling based on data from atomic force microscope measurements [371]. 

The ability of polymeric materials to act at interfaces depends on the manner in which they respond to mechanical stress through their surface viscoelasticity (Gau et al., 1993). In addition, the dynamics of adsorption provides information concerning the processes that occur during surface adsorption. 

Frew NM, Bock EJ, McGillis WR, Karachintsev AV, Hara T, Munsterer T, Jahne B (1995) Variation of the air-water transfer velocity with wind stress and surface viscoelasticity. In Jahne B, Monahan E (eds) Air-Water Gas Transfer. AEON Verlag, Heidelberg, pp 529-541... 

The relationship between dynamic surface tension, y( t ), and surface viscoelasticity (which is one of the parameters relevant to wave damping) is well defined in the literature (Loglio et al. 1994, 1995, Dukhin et al. 1995, Noskov and Loglio 1998, Zholkovskij et al. 2000, Kovalchuk et al. 2000, 2004, 2005, Joos 1999, and references therein). Figures 2-5 also demonstrate a satisfactory sensitivity for marine applications of the measurement technique. 

Figure 5 Surface viscoelasticity as a function of surfactant concentration for DTAB solutions with PAMPS 10%. Data from ref 20...

The mixed layers of flexible polymers and surfactant of opposite charge enhance the stability of the foam films made from the solutions. The stabilization mechanisms are different below and above CAC below CAC, the stabilization is probably associated to the increase in surface viscoelasticity, whereas above CAC, the stabilization is visibly associated to the gel-like aspect of the foam films. More rigid polyelectrolytes produce the opposite effect below CAC. This behaviour might be associated to the different behaviour upon large compression and remains to be understood. 

Wang, X. P., Xiao, X., and Tsui, O. K. C.. Surface Viscoelasticity Studies of Ultrathin Polymer Films Using Atomic Force Microscopic Adhesion Measurements. Macromolecules, Vol. 34,2001, pp. 4180-4185. 

Surface Viscosity of Protein Monolayers. Figure 2 shows the surface viscosity ( H g) of a number of proteins and one polyamino acid as a function of H ( ), The extremely high surface viscoelasticity of protein monolayers appears to be more characteristic of an interacting random chain system than an array of rigid helices. The theory of surface viscosity of Moore and Eyring ), based on the Theory of Absolute Reaction Rates, postulates that the flow of a monolayer consists of movements of flow units, normally molecules, from one equilibrium position to another, over an intermediate activation energy barrier. The equation derived for the coefficient of surface viscosity ( g)... 

The atomic force microscope (AFM) is a promising device for the investigation of materials surface properties at the nanoscale. Precise analysis of adhesive and mechanical properties, and particularly of model polymer surfaces, can be achieved with a nanometer probe. This study distinguishes the different contributions (chemical and mechanical) included in an AFM force-distance curve in order to estabhsh relationships between interfacial tip-polymer interactions and the surface viscoelastic properties of the polymer. 

The preparation, uses, and physieal chemistry of silicone siufactants have been described in a well-known reference [38], focusing on silicone polyoxyalkylene copolymers. This book explores many aspects of SPEs as surfactants, like interfacial processes, surface viscoelasticity, and aggregation, explains the imusual wetting behavior of the trisiloxane surfactants and the ternary phase behavior of mixtures of silicone siufactants with water and silicone oils. That is why we only try to emphasize some newer insights into the subject, reported mainly after year 2000. 

Both bulk phase viscosity (50) and, especially, surface phase viscosity effects would be expected to influence the foaming properties of these mixed systems. Surface phase mapping of the Polymer JR 400/SDS system, using a qualitative test of surface viscoelasticity, has recently been reported (51). A considerable portion of the diagram (Chapter 4, Fig. 16) reveals the existence of surface viscoelasticity, suggesting that even the smallest levels of polymer could affect the foam properties of SDS. Only cursory testing of the... 

The surface viscoelastic properties of various polymers were studied by Taka-hara and co-workers (270). The effect of molecular weight on the surface dynamic viscoelastic properties for PS films and the measurement of surface relaxation processes were, for instance, reported (271). 

A simple method, the talc test suggested and applied by Reigsmond et al. [53], was reported sensitive in qualitatively measuring the surface viscoelasticity of surfactant/polymer solution [54],... 

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