High-speed dynamic-mode atomic force microscopy imaging of polymers: an adaptive multiloop-mode approach

Abstract

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.

Simultaneous hysteresis‐dynamics compensation in high‐speed, large‐range trajectory tracking: A data‐driven iterative control

“…where, respectively, ρ * ⊤,1 = 𝜌 * ⊤,1 , ρ * ⊤,2 = 𝜌 * ⊤,2 ∕𝛾, with 𝜌 * ⊤,1 and 𝜌 * ⊤,2 given by Equation (24), and…”

“…The effect of output disturbance on the stability and precision of the data‐driven ILCs has also been analyzed 19 and further accounted for in the controller design 22 . Superior tracking performance has been experimentally demonstrated, 19 and the technique has been implemented in various applications 23‐25 . However, the stability and performance of the data‐driven ILCs for SHDC has not yet been established.…”

“…22 Superior tracking performance has been experimentally demonstrated, 19 and the technique has been implemented in various applications. [23][24][25] However, the stability and performance of the data-driven ILCs for SHDC has not yet been established. This work is focused on theoretical analysis and experimental demonstration of a data-driven difference-inversion-based iterative control (DDD-IIC) technique 21,26 for SHDC.…”

Large-range high-speed dynamic-mode atomic force microscope imaging: adaptive tapping towards minimal force

“…These limitations of control technique developments in improving TM imaging have been tackled in the recent-developed adaptive multi-loop mode (AMLM) [11,23] technique. The main idea is to introduce an additional feedback loop to regulate the mean value of the probe vibration (called the TM-deflection), and thereby, regulate the interaction force, and then, augment a data-driven online iterative feedforward control to enhance the tracking of the sample topography.…”

A simple way to higher speed atomic force microscopy by retrofitting with a novel high-speed flexure-guided scanner

“…Also, atomic force microscopy has little or no restrictions on sample preparations and experimental environments. AFM can be used for imaging, [1][2][3][4][5][6][7][8][9] force spectroscopy [10][11][12][13] and nano-fabrication. 14,15) In force spectroscopy, an AFM is used for measuring forces between a probe and a sample down to the femto-Newton (fN) range 16) whereas for imaging, the interaction forces between the cantilever tip and the sample is used to construct three-dimensional images of a sample topography with sub-nanometer lateral and sub-angstrom vertical resolutions.…”