The Nanoscale World

# Cantilever selection for measuring adhesion force

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42 Posts
Points 485
David Durham posted on Mon, Jun 10 2013 3:24 PM

Hi,

We are trying to measure the adhesion force between 48 Mm silica beads and silica substrate , and based on the theoretical model the expected value of adhesion is around 10 micro N , so what is the proper type of cantilever should we use???

Thanks

• | Post Points: 12

#### Verified Answer

280 Posts
Points 6,221
Bede Pittenger replied on Mon, Jun 10 2013 4:28 PM
Verified by David Durham

You should choose a cantilever that is sensitive as possible, but does not cause the deflection measurement to saturate or become non-linear.

The force is the spring constant times the deflection sensitivity times the detector voltage (F=K*Sd*V).  If we know K for a given probe type and we know the approximate Sd (this depends on probe type, head, microscope type, and laser spot position), we can calculate the approximate detector voltage.  For best linearity the detector voltage should be in the range -2V to +2V (the system can measure up to +/-12V, but it is less linear, so accuracy will usually be less).

For example, some ballpark numbers for the Multimode are:

 F (nN) K (N/m) ~Sd (nm/V) V Probe 10000 350 75 0.380952 DNISP-HS 10000 150 75 0.888889 DNISP 10000 150 30 2.222222 TAP525A 10000 48 50 4.166667 LTESPA

Based on that I'd start with a TAP525A probe and see how it works.

--Bede

#### All Replies

280 Posts
Points 6,221
Bede Pittenger replied on Mon, Jun 10 2013 4:28 PM
Verified by David Durham

You should choose a cantilever that is sensitive as possible, but does not cause the deflection measurement to saturate or become non-linear.

The force is the spring constant times the deflection sensitivity times the detector voltage (F=K*Sd*V).  If we know K for a given probe type and we know the approximate Sd (this depends on probe type, head, microscope type, and laser spot position), we can calculate the approximate detector voltage.  For best linearity the detector voltage should be in the range -2V to +2V (the system can measure up to +/-12V, but it is less linear, so accuracy will usually be less).

For example, some ballpark numbers for the Multimode are:

 F (nN) K (N/m) ~Sd (nm/V) V Probe 10000 350 75 0.380952 DNISP-HS 10000 150 75 0.888889 DNISP 10000 150 30 2.222222 TAP525A 10000 48 50 4.166667 LTESPA

Based on that I'd start with a TAP525A probe and see how it works.

--Bede

42 Posts
Points 485
David Durham replied on Mon, Jun 10 2013 4:33 PM

Thanks Bede!

• | Post Points: 12
11 Posts
Points 125
mariam replied on Tue, Jun 11 2013 4:22 PM

This may be a bit out of the topic but I would also like to inquire what suggestions you may have for measurements of elastic modulus for ceramic samples  with roughness of 0.4-2 microns..

Thank you

• | Post Points: 12
280 Posts
Points 6,221
Bede Pittenger replied on Wed, Jun 12 2013 12:48 PM

please see the response in your other thread: http://nanoscaleworld.bruker-axs.com/nanoscaleworld/forums/t/1445.aspx

• | Post Points: 10
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