adhesion force measurement using AFM

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Ian Armstrong replied on Wed, Jul 3 2013 2:57 PM

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Hi Husam, 

The easiest way forward for your different chemical composition and shape beads is to look to a company like NovaScan, they do many different standard particle attachments to a variety of cantilevers. They can also do custom orders.

Attaching > 5um beads to cantilevers is fairly straightforward and typically follows the basic procedure: put adhesive and dispersion of particles on a substrate, do force curve with tipless cantilever on adhesive, do force curve on particle. This is easiest on a micromanipulator (I used to use a Singer Instruments MSM400 which is ideally suited to the task). It is also possible with any given AFM though this is usually not as tactile and requires more adherence to a protocol.

Attaching ~1um beads to cantilevers  is tricky due to their small size but not impossible. A colleague of mine did this using our BioScope Catalyst AFM using 60X and 100X objectives on a ILM. This allows you to visualise the particles while following the generic attachment procedure I mentioned above.

Once you have your colloid probes and you want to study how  temp/ humidity affects adhesion between substrate and particle you will need an enclosed cell with a heated sample plate. We have just such a thing for all our top tier AFMs: heater cooler stage with liquid cell for Icon and MultiMode, and perfusing stage incubator with heating sample plate for Catalyst. Once you set up these liquid cell options you can control the heated sample plate and attach a third party humidity system that mixes dry gas flow with water steam flow in a defined way (RH 5% to 95%), and provides a basic flow rate of humid gas into the liquid cell. 

Feel free to google/ visit our site to lookup the various keywords I mentioned above. If you have further questions on this you can contact me offline at ian.armstrong@bruker-nano.com

Best regards

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Husam replied on Tue, Jul 9 2013 11:13 AM

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Hi Ian

Thanks so much for your response.

Regarding the micromanipulator ( Singer Instruments MSM400) , you said , you used to, what do think the minimum bead size can attached using this manipulator.Or this only depends on the optical microscope.

Thanks

Husam