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SensaDyne has several Low Cost and
Mid-Range Surface Tensiometers for
accurate Quality Control Testing of Chemicals and Formulations
Surface tension will dictate whether a coating will wet and spread over,
or retract from, a solid surface. Surface tension is the tangential molecular force of attraction that "holds" a liquid together within its own confines in the presence of air. This surface tension force is expressed
in dynes/cm (or milliNewtons/meter).
Measurement of DYNAMIC SURFACE TENSION can
directly predict the Quality of a coating and its ability to perform as
required
The process of applying a fluid onto a substrate is a dynamic one in
which surface tension varies as the speed of the application varies
whenever active surfactants are used. Surfactants are used because of
their ability to reduce surface tension in water-based and solvent-based
formulations.
The relevant parameter in designing formulations is
dynamic surface tension rather than equilibrium surface tension,
since it can take
from several seconds to several minutes for surfactant molecules to
diffuse to the air/fluid interface where they can lower the surface tension to its
lowest (equilibrium) level.
Dynamic surface tension directly impacts the quality of spreading and
adhesion. Surfactants used in fluid formulations tend to be quite surface
active, and can vary significantly with respect to diffusion rate,
depending on molecular weight and structure. Formulators that have a
basic understanding of the principles of dynamic surface tension, and
use the SensaDyne tensiometers to make dynamic (and equilibrium) surface tension measurements, can solve formulation quality problems and optimize their coating system operations.
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