Ring tensiometer

Figure 2.11 Du-Notly ring tensiometer and Wilhclmy-platc method.

Important techniques to measure the surface tension of liquids are the sessile drop method, the pendant or sessile bubble method, the Du-Notiy ring tensiometer, and the Wilhelmy-plate method. 

Experimental Procedure -- The surface tensions of Triton X-100 solutions, with or without other additives, were measured using a du Nouy ring tensiometer (Fisher Scientific Company) at 25°C. 

Surface Tension Measurements. The surface tension of each HA or FA solution was measured using a du Nouy ring tensiometer as previously described (13). 

Aqueous viscosity was measured at room temperature with a Brookfield and Ubbelohde viscometer. Intrinsic viscosities were measured by a five-point dilution method no shear-rate corrections were made for the data. Interfacial tension was measured with a DuNouy ring tensiometer against toluene at various polymer concentrations. The formulations used to evaluate the HMHECs for latex paints have been described elsewhere (5). 

The graphs shown in Fig. 4.35 are the dynamic surface tensions of three mixtures of CioDMPO and CmDMPO measured with the maximum bubble pressure method MPT2 (O) and ring tensiometer TE2 (O). Although there is a general theoretical model to describe the adsorption kinetics of a surfactant mixture, model calculations are not trivial and a suitable software does not exists. 

Surface tension measurements reported in Table 1 were performed using a du Nouy ring tensiometer. They include appropriate corrections for surface deformation (23). Cleaning of the surfaces was accomplished with alternate washings of isopropanol and methanol. 

Lunkenheimer, K. and Wantke, K. D., On the applicability of the du Nouy (ring) tensiometer method for the determination of surface tensions of surfactant solutions, J. Colloid Interface ScL, 66, 579-581 (1978). 

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