Fluid Operation
General Fluid Operation
Rev. B
MultiMode SPM Instruction Manual
125
The male Luer
fi
ttings can be inserted into the
fl
uid ports on the front of the
fl
uid cell, and the
opposite side of the
fi
tting is connected to the silicone tubing. The female Luer
fi
ttings connect the
silicone tubing to the syringe.
Use of the O-rings is optional. Instructions for operating the
fl
uid cell with and without the O-ring
are detailed in this chapter. The previous O-ring design was based on a circular cross-section. The
new O-ring design has an “S” shaped cross-section with thin,
fl
exible walls. This new design makes
insertion of the O-ring easier, reducing the chances of leaking and minimizing imaging artifacts
caused by lateral friction.
Two additional
fl
uid cell designs are available from Veeco:
•
Contact Mode electrochemical
fl
uid cell (Model ECFC)
•
TappingMode electrochemical
fl
uid cell (Model MMTMEC)
These
fl
uid cells have additional ports for the insertion of a reference electrode and a counter
electrode.
Note:
It is necessary to connect an external potentiostat to perform electrochemical
measurements. Contact Veeco for more information.
8.2.1 Clean Fluid Cell and O-ring
To reduce contamination problems and to obtain high-quality images, clean the
fl
uid cell, and O-
ring if applicable, as follows:
1. While soaking the fluid cell and O-ring in warm, soapy water, place a few drops of liquid
dish soap on them. Use nonabrasive soap to prevent scratching the glass surfaces.
2. Gently rub the fluid cell and O-ring with a cotton swab or finger. Avoid scratching the glass
surface with abrasive material.
3. Using distilled water, rinse the fluid cell and O-ring of all soap.
4. Using 0.2µm-filtered, compressed air or dry nitrogen, blow dry the fluid cell until all
moisture evaporates.
8.2.2 Select the Probe
AFM probes featuring low stiffness cantilevers produce the best results for biological applications.
We recommend sharpened tips to start: 100µm (“short”), V-shaped cantilevers with oxide-
sharpened silicon nitride tips; for example, models NP-S (standard) or NP-STT (oriented twin tip).
Stiffer etched silicon probes (model FESP, single beam, 225µm long) used at very small oscillation
amplitudes also obtain good results. Experiment to
fi
nd which probes work best for your sample.
Note:
For additional information on selecting a probe, please refer to the applications
note “
Choosing AFM Probes for Biological Applications
.”
