attension Theta, User Manual

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measured by inducing a small and controlled perturbation (an oscillation or a pulse) to a pendant drop (or
a bubble) and simultaneously recording the change in the interfacial tension and the drop area. If the
interfacial deformation is sinusoidal the interfacial elasticity and viscosity can be determined from the
phase shift of the interfacial tension and area response.
The perturbation is achieved with a piezo-pump enclosed in a chamber. The piezo-pump is driven
through a pulse modulating electronics units.
Technical specifications
Perturbation principle Piezo-electric membrane enclosed in a chamber
Frequency range 0-100 Hz (practical useful range 0.01
– 10 Hz)
Frequency resolution 0.001 Hz
Maximum volume amplitude 1
μ
l
Sample liquid volume
needed
5
μ
l
Connections
The pump chamber contains the piezo pump that oscillates the drop at the end of the needle. A syringe
is used as the liquid reservoir. A Teflon tube is be used to connect the syringe to the pump or the pump
to the needle. The pump is controlled by the electronics unit.
Connect the serial cable to the port of the control unit of the PD 200 and then to the AUX X port of Theta
with the cable supplied. Then connect the pump to the control unit of the PD 200, after which PD 200 is
ready to use.
Using the PD 200
Start OneAttension software and begin a Pulsating drop experiment. PD 200 device controls will appear
automatically and adjustable parameters in the recipe sheet (Figure 4.27):
Oscdrop device controls:
Start: Starts the oscillation according to the experimental parameters in the recipe sheet. Measurement
will not be recorded.
Stop: Stops the oscillation.