Surface Potential Sensor

The KSV NIMA Surface Potential Sensor is a compact and highly sensitive characterisation instrument that offers complementary data on the packing and orientation of Langmuir films. The KSV NIMA Surface Potential Sensor (SPOT) measures the potential difference above and below the film.

Applications

The KSV NIMA Surface Potential Sensor allows complementing data from surface pressure - area isotherm measurements that are obtained from a Langmuir and Langmuir-Blodgett Trough. It allows the determination of monolayer composition, molecular orientation, degree of molecular dissociation and molecular interactions at the interface. The most common applications are:

· Determining effective dipole moments
The KSV NIMA SPOT can be used to determine effective dipole moments through simple surface potential measurements of a compressed film.

· Determining molecular orientation
The KSV NIMA SPOT can be use to obtain information on molecular orientation by observing changes in surface potential and combining the data with surface pressure information.

· Film electronic structure characterisation
Even the smallest change in the electronic structure of molecules can be detected by measuring the change in surface potential.

· Molecular structure characterisation
Quantify the effects of changes to molecular structure through positional offsets and peak values of the surface potential plots.

· Complex formation monitoring
Observe and follow complex formations between monolayers, subphase species or adsorbates.

For measurement examples, please download the KSV NIMA SPOT brochure.

Technology

The KSV NIMA Surface Potential Sensor measures the potential difference above and below the film and is sensitive to the sum of all the individual dipole moments. The changes in surface potential are measured by detecting the potential difference between the vibrating plate which is placed above the monolayer and the counter electrode which is immersed in the subphase below the monolayer. Please visit the surface potential sensing technology page for more information about the technology.

Main features and benefits

· Accurate and reproducible measurements
The non-contact and non-destructive vibrating plate capacitor method ensures very good accuracy and reproducibility.

· Software integrated to the KSV NIMA L and LB Trough Software
The KSV NIMA Surface Potential Sensor does not require any additional software and can be easily installed by a simple plug and play operation. The latest version of KSV NIMA LB Software, supplied with all KSV NIMA Langmuir and Langmuir-Blodgett Deposition Troughs, displays the recordings of the surface pressure and surface potential on the same plot. Colour coded axes and plots ensure that the two recordings are clearly presented.

· Easy set up
The KSV NIMA Surface Potential Sensor connects directly to your existing KSV NIMA Interface Unit, supplied with all KSV NIMA Langmuir and LB Deposition Troughs. The KSV NIMA SPOT is provided with a flexible stand allowing rapid and easy integration to your trough. Furthermore, the instrument is factory calibrated for a quick start up.

Technical specification

· Measurement:
Input range:   -5V to +5V
Sensitivity:   +/- 1mV
Drift: +/- 5mV/h
Height dependency: 10mV/mm
Response time:   Proportional to distance but less than 1s when positioned 1mm above monolayer
Calibration:   Factory calibrated

· Hardware:
Measuring head dimensions: 100x85x20mm
Probe diameter: 16mm
Stand base height: 19mm
Maximum sensor height: 160mm
Counter-electrode plate dimensions: 35x50x2mm
Vertical electrode arm length: 20mm

· Software:
Fully incorporated into KSV NIMA LB Software for Langmuir and Langmuir-Blodgett Troughs.

Compatibility

It is recommended to use the KSV NIMA Surface Potential Sensor together with a KSV NIMA Langmuir, Langmuir-Blodgett or Microscopy Trough to be able to combine surface pressure and surface potential measurements. The KSV NIMA Surface Potential Sensor can also be used with other Troughs along with a KSV NIMA Interface Unit.