[Spm] different deflection sensitivity in two phases

[Yang Gan]

Dear Sam,

It is very likely that different phases are differing in their rigidity. So you are observing different mechanical properties of phases! Thus, I do not believe your problem is really a problem. It might lead to a new direction of your research!

Technically, you may calibrate the deflection sensitivity of the probe and scanner by collecting force curves against a rigid substrate like glass or silica. The deflection sensitivity should thus be fixed for following measurements with your membrane samples only if you do not change the probe and adjust the lasers. Otherwise, you will find varying sensitivity values by errorly measuring it on soft samples.

Please contact me offline for further discussions.

Regards,
Yang

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Yang Gan
Professor, PhD
Department of Catalysis Science & Engineering (Prep.)
School of Chemical Engineering & Technology
Harbin Institute of Technology
No.92, West Da-Zhi Street, Harbin
Heilongjiang 150001
P. R. China
Tel: +86-451-86403239
E-mail: ygan at hit.edu.cn
Web: http://3www.hit.edu.cn/experts/prof.asp?id=1182
Section editor: Chemistry Central Journal (CCJ) (indexed by ISI, PubMed Central, Scopus, CAS and Google Scholar)
Home page of CCJ: http://journal.chemistrycentral.com
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Message: 4
Date: Sun, 30 Nov 2008 20:28:44 +0000
From: Sam Engler <smtygtyg at hotmail.com>
Subject: [Spm] different deflection sensitivity in two phases
To: <spm at spmlist.di.com>
Message-ID: <BAY119-W10DE244018FB1F05C3000AD1060 at phx.gbl>
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Hello Everyone,

I have a multiple composition lipid membrane sample, which phase-separated into 3 phases. During the force-displacement measurements, the slopes of the f-d curves within phase C are different than the slopes within phase A and B. I've tried different cantilevers and this is consistent. My questions are (1) why the deflection sensitivity of the cantilever is changing from one phase to another phase? (2) should I change to stiffer cantilevers?

Any comments will be appreciated. 

Thanks,
Sam,

Sam Engler, Ph.D

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