Extension of AFM-based viscoelasticity measurement into a frequency-resolved analysis is attempted. A cantilever immersed into and interacting with distilled water was employed for the trial system. Using a home-built wideband magnetic excitation AFM, a step force with a transient time less than 1micros is applied to the AFM cantilever and its deflection is measured. The 1st and 2nd mode resonance ringing of the cantilever was suppressed using quality-factor-control technique, so that the measurement system becomes equivalent to driving a resonance-free virtual cantilever within the bandwidth limited by the surviving 3rd mode resonance. From the obtained response of the cantilever deflection, a frequency-dependent complex compliance of the cantilever-water system was derived in a frequency range of 1-100kHz. Effect of water confining between the tip and a mica substrate is discussed.
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http://dx.doi.org/10.1016/j.ultramic.2010.02.020 | DOI Listing |
Subcell Biochem
December 2024
Department of Physics of the Condensed Matter, C03 and IFIMAC (Instituto de Física de la Materia Condensada). Universidad Autónoma de Madrid, Madrid, Spain.
Atomic force microscopy (AFM) makes it possible to obtain images at nanometric resolution, and to accomplish the manipulation and physical characterization of specimens, including the determination of their mechanical and electrostatic properties. AFM has an ample range of applications, from materials science to biology. The specimen, supported on a solid surface, can be imaged and manipulated while working in air, ultra-high vacuum or, most importantly for virus studies, in liquid.
View Article and Find Full Text PDFNanoscale
January 2025
Univ. Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33400 Talence, France.
Tip-enhanced Raman spectroscopy (TERS) is a powerful technique for nanoscale chemical imaging. However, its worldwide expansion is still limited by the challenging fabrication of cheap, robust and efficient TERS tips as optical nanosources to amplify the Raman signal. An original method based on bipolar electrodeposition is described here to prepare gold-coated AFM cantilevers used as TERS tips.
View Article and Find Full Text PDFLangmuir
November 2024
Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907-2100, United States.
The atomic force microscope (AFM), as it is able to characterize surface topography as well determine the AFM cantilever tip-surface force, proves effective at estimating the value of the Hamaker constant, , for a given solid material. Two main AFM-based methods have been proposed for estimating values of . In the approach-to-contact (AtC) method, Hamaker constants are inferred from the deflections at which the AFM tip first jumps into contact with the substrate.
View Article and Find Full Text PDFFaraday Discuss
October 2024
Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee, 11 89081 Ulm, Germany.
Platinum-black (Pt-B) has been demonstrated to be an excellent electrocatalytic material for the electrochemical oxidation of hydrogen peroxide (HO). As Pt-B films can be deposited electrochemically, micro- and nano-sized conductive transducers can be modified with Pt-B. Here, we present the potential of Pt-B micro- and sub-micro-sized sensors for the detection and quantification of hydrogen (H) in solution.
View Article and Find Full Text PDFAnal Chem
October 2024
Nanoscale Devices Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
Photothermal induced resonance (PTIR), also known as atomic force microscopy-infrared (AFM-IR), enables nanoscale IR absorption spectroscopy by transducing the local photothermal expansion and contraction of a sample with the tip of an atomic force microscope. PTIR spectra enable material identification at the nanoscale and can measure sample composition at depths >1 μm. However, implementation of quantitative, multivariate, nanoscale IR analysis requires an improved understanding of PTIR signal transduction and of the intensity dependence on sample characteristics and measurement parameters.
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