A standard AFM tip doesn't do very well at measuring hydrophobic attraction, but modify it with a colloid tip and it's a different story.

Here’s an interesting problem: how do you create an atomic force microscope probe that will allow you to measure hydrophobic attraction?  Hydrophobic attraction is the “unusually strong and long-range attractive force exhibited between hydrophobic surfaces in water.”  A traditional hard-tip AFM probe will not be hydrophobic, but if you try to modify it with some kind of hydrophobic-coated bead, inconsistencies in the surface area will make calibration almost impossible.  That’s why researchers at Zhejiang University in Hangzhou, China developed a collloid AFM tip. They prepared the silicon sample substrate with a preliminary ultrasonic cleaning.

For further information visit www.ncbi.nlm.nih.gov.

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