Nonlinear Interaction Force Analysis of Microcantilevers Utilized in Atomic Force Microscopy

Author(s):  
Sohrab Eslami ◽  
Nader Jalili ◽  
Ali Passian ◽  
Laurene Tetard ◽  
Thomas Thundat

This paper presents an Euler-Bernoulli microcantilever beam model utilized in non-contact Atomic Force Microscopy (AFM) systems. A distributed-parameters modeling is considered for such system. The motions of the microcantilever are studied in a general Cartesian coordinate with an excitation at the base such that beam end with a tip mass is subject to a general force. This general force comprising of two attractive and repulsive parts with high power terms is taken as the atomic intermolecular one which has a relation with the displacement between the tip mass and the surface such that the total general force will be in the form of an implicit nonlinear equation. It is most desired to observe the effects of the base excitation in high frequencies on the tip van der Waals interaction force. Hence, the general force will produce a peak in the FFT spectrum corresponding to the frequency of the base.

2017 ◽  
Vol 8 ◽  
pp. 1563-1570 ◽  
Author(s):  
Juan Ren ◽  
Qingze Zou

Adaptive multiloop-mode (AMLM) imaging to substantially increase (over an order of magnitude) the speed of tapping-mode (TM) imaging is tested and evaluated through imaging three largely different heterogeneous polymer samples in experiments. It has been demonstrated that AMLM imaging, through the combination of a suite of advanced control techniques, is promising to achieve high-speed dynamic-mode atomic force microscopy imaging. The performance, usability, and robustness of the AMLM in various imaging applications, however, is yet to be assessed. In this work, three benchmark polymer samples, including a PS–LDPE sample, an SBS sample, and a Celgard sample, differing in feature size and stiffness of two orders of magnitude, are imaged using the AMLM technique at high-speeds of 25 Hz and 20 Hz, respectively. The comparison of the images obtained to those obtained by using TM imaging at scan rates of 1 Hz and 2 Hz showed that the quality of the 25 Hz and 20 Hz AMLM imaging is at the same level of that of the 1 Hz TM imaging, while the tip–sample interaction force is substantially smaller than that of the 2 Hz TM imaging.


Author(s):  
Sudipta Dutta ◽  
Mahesh Kumar Singh ◽  
M. S. Bobji

Atomic force microscopy based force-displacement spectroscopy is used to quantify magnetic interaction force between sample and magnetic cantilever. AFM based F–D spectroscopy is used widely to understand various surface-surface interaction at small scale. Here we have studied the interaction between a magnetic nanocomposite and AFM cantilevers. Two different AFM cantilever with same stiffness but with and without magnetic coating is used to obtain F–D spectra in AFM. The composite used has magnetic Ni nanophase distributed uniformly in an Alumina matrix. Retrace curves obtained using both the cantilevers on magnetic composite and sapphire substrate are compared. It is found for magnetic sample cantilever comes out of contact after traveling 100 nm distance from the actual point of contact. We have also used MFM imaging at various lift height and found that beyond 100nm lift height magnetic contrast is lost for our composite sample, which further confirms our F–D observation.


2005 ◽  
Author(s):  
Yanxia Wang ◽  
Yanning Li ◽  
Xing Fu ◽  
Jun-Yong Cui ◽  
Xiaotang Hu

MRS Advances ◽  
2018 ◽  
Vol 3 (42-43) ◽  
pp. 2617-2626 ◽  
Author(s):  
MALESELA K. MOUTLANA ◽  
SARP ADALI

ABSTRACTIn this study we investigate the motion of a torsionally restrained beam used in tapping mode atomic force microscopy (TM-AFM), with the aim of manufacturing at nano-scale. TM-AFM oscillates at high frequency in order to remove material or shape nano structures. Euler-Bernoulli theory and Eringen’s theory of non-local continuum are used to model the nano machining structure composed of two single degree of freedom systems. Eringen’s theory is effective at nano-scale and takes into account small-scale effects. This theory has been shown to yield reliable results when compared to modelling using molecular dynamics.The system is modelled as a beam with a torsional boundary condition at one end; and at the free end is a transverse linear spring attached to the tip. The other end of the spring is attached to a mass, resulting in a single degree of freedom spring-mass system. The motion of the tip of the beam and tip mass can be investigated to observe the tip frequency response, displacement and contact force. The beam and spring–mass frequencies contain information about the maximum displacement amplitude and therefore the sample penetration depth and this allows


2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Bumjoon Choi ◽  
Taehee Kim ◽  
Sang Woo Lee ◽  
Kilho Eom

Amyloid fibrils have recently received much attention due to not only their important role in disease pathogenesis but also their excellent mechanical properties, which are comparable to those of mechanically strong protein materials such as spider silk. This indicates the necessity of understanding fundamental principles providing insight into how amyloid fibrils exhibit the excellent mechanical properties, which may allow for developing biomimetic materials whose material (e.g., mechanical) properties can be controlled. Here, we describe recent efforts to characterize the nanomechanical properties of amyloid fibrils using computational simulations (e.g., atomistic simulations) and single-molecule experiments (e.g., atomic force microscopy experiments). This paper summarizes theoretical models, which are useful in analyzing the mechanical properties of amyloid fibrils based on simulations and experiments, such as continuum elastic (beam) model, elastic network model, and polymer statistical model. In this paper, we suggest how the nanomechanical properties of amyloid fibrils can be characterized and determined using computational simulations and/or atomic force microscopy experiments coupled with the theoretical models.


2016 ◽  
Vol 120 (42) ◽  
pp. 10932-10935 ◽  
Author(s):  
Hweiyan Tsai ◽  
Zihkai Chen ◽  
Huiwen Deng ◽  
Sinmei Tsai ◽  
C. Bor Fuh

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