KSV-SPOT1 - Surface Potential Meter

KSV-SPOT1 is a small computer controlled stand-alone surface potential measuring head. KSV  SPOT1 is based on the non-contact and non-destructive vibrating plate capacitor method. The low inaccuracy, minimal drift and high reproducibility are properties that proves the uniqueness of KSV-SPOT1. This also guarantees a high sensitivity and stability for the measurements.

KSV-SPOT1 enables you to complement your surface pressure - area data with the more sensitive surface potential data. Thus, giving you for example the following additional information about your monolayers.

+ Composition
+ Dissociation degree
+ Orientation
+ Interaction
+ Adsorption  

Due to its stand-alone property the KSV-SPOT1 is not only limited to KSV instruments and monolayer measurements, it can of  course also be used for any other applications where surface potentials are required.

Specifications

Measuring principle	Vibrating plate capacitor method
Dynamic range	-4 to +4 V
Sensitivity	1 mV
Response time	2 seconds
Inaccuracy	+/- 3 mV
Height dependency	2 mV/mm
Drift	Negligible in air, 3 mV/h with subphase
Probe diameter	17 mm
Sensor head dimensions	100 x 20 x 85 mm3
Mounting	Rough height adjustment +/- 20 mm Micromanipulator, +/- 10 mm
Operational voltage	90-264 V (Automatic), 50/60 Hz
Computer requirements	IBM compatible running Windows 95/98/NT/2000

 

Example measurements

Upper figure shows a surface pressure - area isotherm of stearic acid complemented with the surface potential measured with the KSV-SPOT1.  The subphase used was pure water with pH = 4 giving a maximum surface potential value of 349 +/- 2 mV (average of 8 measurements). This value corresponds very well with the value found in the literature. The lower figure shows three consecutive measurements of the surface potential of stearic acid monolayers demonstrating the high accuracy and reproducibility of the KSV-SPOT1 measuring head. 

Block diagram of the measuring circuit

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