Real-time probe based quantitative determination of material properties at the nanoscale

Abstract

Tailoring the properties of a material at the nanoscale holds the promise of achieving hitherto unparalleled specificity of the desired behavior of the material. Key to realizing this potential of tailoring materials at the nanoscale are methods for rapidly estimating physical properties of the material at the nanoscale. In this paper, we report a method for simultaneously determining the topography, stiffness and dissipative properties of materials at the nanoscale in a probe based dynamic mode operation. The method is particularly suited for investigating soft-matter such as polymers and bio-matter. We use perturbation analysis tools for mapping dissipative and stiffness properties of material into parameters of an equivalent linear time-invariant model. Parameters of the equivalent model are adaptively estimated, where, for robust estimation, a multi-frequency excitation of the probe is introduced. We demonstrate that the reported method of simultaneously determining multiple material properties can be implemented in real-time on existing probe based instruments. We further demonstrate the effectiveness of the method by investigating properties of a polymer blend in real-time.

Nanomechanical mapping of soft materials with the atomic force microscope: methods, theory and applications

“…[29][30][31][172][173][174][175][176][177][178][179][180][181][182] Those methods are classified in two groups, time-resolved 29,30,[172][173][174][175][176] and force reconstruction methods. [177][178][179][180][181][182] To understand how a dynamic AFM method transforms the time dependencies of the observables into force-distance curves is pertinent to distinguish between flexural and torsional harmonics. 20,30,31,183 An harmonic oscillation vibrates at a frequency that is a multiple of the excitation frequency.…”

“…Several methods were developed to overcome this limitation by recording and processing amplitude and phase shift of the tip's oscillation as a function of the average tip-sample distance. [177][178][179][180][181][182] Fig. 7d shows some experimental amplitude and phase-shift distance curves.…”

“…The amplitude and phase shift-distance curves can be generated either by using the standard AM-AFM configuration 182 or by implementing other modulation methods. 180,181 The integration enables to reconstruct the force from amplitude and phase shift-distance curves. In general, these methods are less efficient than FV because they involve more processing steps so very few applications have been reported.…”

Force reconstruction from tapping mode force microscopy experiments

“…The method of slowly varying parameters has previously been used to calculate the average force [28], to derive an state-space model of a cantilever under feedback control [50] or to discuss high-resolution imaging with different feedback architectures [51].…”

Fast nanomechanical spectroscopy of soft matter

“…In the recent years, several methods have been proposed to complement the high spatial resolution of the force microscope with quantitative information about the mechanical properties of the interface [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] . In fact, the goal of combining topography with compositional contrast can be traced back to the origin of dynamic AFM with the development of phase-imaging AFM.…”