This work presents a model to predict the effect of surface stresses on the ith-mode bending resonant frequency of microcantilevers and its experimental validation. With this model, one can calculate the surface stress acting upon the microcantilever solely by measuring resonant frequencies whereas previously one needed to measure the deflection. Resonant frequency measurement has distinct advantages in terms of ease and accuracy of measurement.

The mechanical response of a multiwalled carbon nanospring was examined with an atomic force microscope. Cantilever deflection, oscillation amplitude, and resonance were simultaneously monitored during the cycled movement of the scanner. A nonlinear response of the nanospring was observed, consistent with compression and buckling of the nanospring. This is the first reported measurement of a shift in the cantilever resonance frequency as a result of the interaction of a nanospring-tipped cantilever with the substrate.

A method is presented to determine the geometry of tipless microcantilevers by measuring the resonance frequencies of at least one of their bending, lateral and torsional resonance modes, and having knowledge of the beam's elastic modulus, Poisson's ratio and density. Once the geometry is known, the beam's stiffness and mass can be calculated. Measurement of multiple modes allows for multiple estimates of cantilever geometry. Multiple data points from the experimental results show that this approach yields dimensional values accurate to roughly 2.5% as compared to SEM-determined length, width and thickness. Stiffness values determined with this new technique are roughly 4.7% and 6.5% less than two existing characterization methods (i.e., Sader's method and Euler–Bernoulli beam theory predictions), and roughly 16% greater than Hutter and Bechhoefer's stiffness determination method.

An important figure of merit in atomic force microscopy is the spring constant of the cantilever probe. To create high aspect ratio tips, cantilever probe manufacturers commonly use dynamic etch techniques that modify the shape and dimensions of both the tip and the beam. Most of the methods used to determine beam stiffness assume a rectangular cross section even though the commonly used etches produce beams with trapezoidal cross sections. We present herein an improved method for determining beam stiffness that takes into account the actual geometry of the cantilever.

Lesson: Scanning Probe Microscopy: "feeling" what you can't see at the nanometer scale Standards:HS-PS1-3. Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.HS-PS2-6. Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.HS-PS2-1. Analyze data to support the claim that Newton's second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.

Nanotube/polymer composite interfaces are of interest for next generation composites. We have examined the adhesion between thiolated AFM cantilever tips and single walled carbon nanotube paper using chemical force microscopy. We have observed a direct correlation of adhesion force with respect to the thiol terminal group (NH2 > CH3 > OH). Our findings demonstrate that the interfacial interactions between single walled carbon nanotubes and terminally functionalized hydrocarbons can be evaluated with an atomic force microscope, provided that one accounts for variations in contact area caused by tip shape and sample topology.

Tipless thermoplastic microcantilevers suitable for chemical and biological sensing applications were fabricated by injection moulding. Their stiffnesses and resonant frequencies were each determined by two techniques. Polystyrene beams produced by this method exhibited stiffnesses ranging from 0.01 to 10 N m−1, making them feasible for biosensing applications. The approach proved repeatable with low standard deviations on the parameters measured on 22 microcantilever beams (stiffness and first-mode resonant frequency) made from the same mould. The variations were much lower than those of similar, commercially available, silicon-type beams. The polymeric microcantilevers were shown to be of at least equal calibre to commercially available microcantilevers.

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