Dear PUSPM community,
I hope everyone's summer went well. The Purdue University Scanning Probe Microscopy (PUSPM) user's group seminar series will be continued during the Fall 2009 semester. The first talk of the semester will be this Friday, August 28th in Birck 2001.
Daniel Kiracofe, a PHD student in Professor Raman's research group will be giving a talk titled "On eigenmodes, stiffness, and sensitivity of atomic force microscope cantilevers in air versus liquids." Please see the below abstract for more information. Pizza will be provided at 11:30 a.m., the talk will begin at noon, and end by 1:00 p.m..
Please see the attached files. Or visit our website (www.engineering.purdue.edu/PUSPM) for more information about the upcoming semester.
I hope to see you there, Ryan Wagner PUSPM student coordinator
P.S. To be removed from this email list send the request to rbwagner@purdue.edu .
Abstract: The effect of hydrodynamic loading on the eigenmode shapes, modal stiffnesses, and optical lever sensitivities of Atomic Force Microscope (AFM) microcantilevers is investigated by measuring the vibrations of such microcantilevers in air and water using a scanning laser Doppler vibrometer. It is found that for rectangular tipless microcantilevers, the measured fundamental and higher eigenmodes and their equivalent stiffnesses are nearly identical in air and in water. However, for microcantilevers with a tip mass or for picket shaped cantilevers there is a marked difference in the second (and higher) eigenmode shapes between air and water that leads to a large decrease of modal stiffness in water as compared to air, as well as a decrease in optical lever sensitivity. These results are explained in terms of hydrodynamic interactions of microcantilevers with non-uniform mass distribution. The results clearly demonstrate that tip mass and hydrodynamic loading must be taken into account in calibration while using higher-order eigenmodes in dynamic AFM.
Deborah S. Starewich Administrative Assistant to Prof. Timothy Sands Birck Nanotechnology Center 1205 W. State Street, Room 1027 West Lafayette, IN 47907-2057 765-494-3509 765-496-8383 (fax) dstarewi@purdue.edu Www.nano.purdue.edu