Discrimination of adhesion and viscoelasticity from nanoscale maps of polymer surfaces using bimodal atomic force microscopy

Abstract

The simultaneous excitation and measurement of two eigenmodes in bimodal atomic force microscopy (AFM) during sub-micron scale surface imaging augments the number of observables at each pixel of the image...

Accurate Wide-Modulus-Range Nanomechanical Mapping of Ultrathin Interfaces with Bimodal Atomic Force Microscopy

“…It involves the application of the virial theorem to excited modes. , This leads to two independent equations, one for each excited mode where z i is the deflection of the excited modes and z is the total cantilever deflection ( z ≈ z 0 + z 1 + z 2 ). In many situations of interest, T is well approximated by the period of the first eigenmode ( T ≈ T 1 ). , The above equation can be solved by two independent approaches. First, by integrating the equation of motion of the excited modes, it has been shown that for A 01 ≫ A 02 , We have used the subscript m to indicate that the virials are directly determined (measured) from the observables ( A 1 , A 2 , ϕ 1 , Δ f 2 ).…”

“…In many situations of interest, T is well approximated by the period of the first eigenmode (T ≈ T 1 ). 50,52 The above equation can be solved by two independent approaches. First, by integrating the equation of motion of the excited modes, it has been shown that for…”

“…It combines high spatial resolution (angstrom or nanoscale) with quantitative accuracy for the determination of the Young’s modulus. Recently, the method has been extended to measure adhesion forces on the nanoscale …”

“…Recently, the method has been extended to measure adhesion forces on the nanoscale. 52 A variety of theories and simulations have supported or demonstrated the capabilities of bimodal AFM. 53−63 Currently, it is the only method that provides nanomechanical maps at 5 frames per second (high speed).…”

Chemical bond imaging using torsional and flexural higher eigenmodes of qPlus sensors

“…In case of conventional silicon cantilevers the simultaneous actuation of their fundamental and higher flexural or torsional eigenmodes can offer, for example, more channels of information, higher image contrast or increased force sensitivity. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] The suitability of qPlus sensors for the application of such modern multifrequency operation modes has, however, only been scarcely studied until now. [48][49][50][51][52][53][54] For example, it has been observed that flat crystalline NaCl and KBr surfaces can be imaged with atomic resolution using a higher eigenmode or bimodal AFM in UHV and ambient conditions.…”