Europhys. Lett.
Volume 62, Number 5, June 2003
Page(s) 671 - 676
Section General
Published online 01 May 2003
DOI: 10.1209/epl/i2003-00426-2
Europhys. Lett., 62 (5) , pp. 671-676 (2003)

Apparent hardening of soft samples through Q factor change in AFM

F. Dubourg, J. P. Aimé, G. Couturier and J. Salardenne

CPMOH University Bordeaux I - 351 Cours de la Libération, F-33405 Talence, France

(Received 18 November 2002; accepted in final form 21 March 2003)

This experimental work aims to show that the Q factor value is an experimental parameter of great importance to access different soft materials properties with a dynamic Atomic Force Microscope. Two dynamic modes have been compared, amplitude modulation, usually called Tapping mode, and the frequency modulation mode. With Tapping, at low or intermediate Q values, the images mostly contain mechanical information. At very high Q values, more than 104, obtained in a vacuum, the experiments performed on a polyisoprene sample show that a pure topographic image can be recorded with Tapping, but not with frequency modulation. For large enough Q values, even on a very soft sample, images in which only topographic information is revealed can be obtained and are in agreement with theoretical predictions.

07.79.Lh - Atomic force microscopes.
68.37.Ps - Atomic force microscopy (AFM).
87.64.Dz - Scanning tunneling and atomic force microscopy.

© EDP Sciences 2003