Location: WUR Building 309, room C94
Aim of the seminar series is informing people about nanotechnology research in Wageningen and other institutions in the Netherlands by Pieter Stoeve.
Programme
13.30 Pieter Stroeve: Measurement and Sensing
14.30 Mieke Kleijn: Measurement of surface using the atomic force microscope
The atomic force microscope (AFM) has been developed to provide high-resolution (in the ideal case atomic) topographical analysis, applicable to all types of surfaces in air, gas and liquid. The basic imaging principle is very simple: a sample attached to a piezoelectric positioner is scanned beneath a sharp tip attached to a sensitive cantilever spring. Undulations in the surface lead to deflection of the spring, which is monitored optically. The images obtained are critically dependent on the force acting or applied between tip and sample, and optimal imaging conditions are inevitably sample dependent. Therefore, quantifying tip-sample interaction forces has been essential in the probe microscopy methodology from the very start, and within a short time span this resulted in its application to surface force measurements. With appropriate calibration of the spring constant and piezo scanner movement, one can quantify both the separation dependence of the interaction forces on tip-sample approach and the adhesion force on removal. However, since the geometry of the AFM tip is ill-defined, quantitative comparison to theoretical models on surface forces is not possible. This problem is solved by attachment of a (typically spherical) particle to the tip and this refinement is referred to as colloid probe microscopy. A further distinct advantage is that interactions and/or adhesion can be studied under chemically realistic conditions by using a particle of interest as the probe. The ins and outs of colloid probe microscopy will be presented, illustrated by various results of surface force measurements as performed in our lab over the past 10 years.
Pieter Stroeve: Nanotechnology in the Life Sciences, overall scope
Nanotechnology is an exiting interdisciplinary field that has tremendous potential to develop new science and novel materials, devices, sensors, and drug delivery . The development of this dynamic field depends on close collaboration between chemists, physicists, biologists, material scientists, and engineers to bring together their expertise to unique problems. The seminar series has been developed to examine various aspects of nanotechnology that have impact on the life sciences. The seminar series contains general talks that give overviews in several areas of the life sciences: measurement and detection, materials, self-assembly, environment, and the life sciences. Although the seminar series will refer to developments in the electronic industry, the developments of nanotechnology will not be reviewed. Each general talk will be followed by a specific research seminar in the area of nanotechnology. The specific talks give an insight on some of the research conducted at WUR and other institutions in the Netherlands.