Repulsive bimodal atomic force microscopy on polymers

• Alexander M. Gigler,
• Christian Dietz,
• Maximilian Baumann,
• Nicolás F. Martinez,
• Ricardo García and
• Robert W. Stark

Beilstein J. Nanotechnol. 2012, 3, 456–463, doi:10.3762/bjnano.3.52

• magnitude smaller than the first two fundamental eigenmodes. Thus, repulsive bimodal imaging of polymer surfaces yields a good signal quality for amplitude ratios smaller than A01/A02 = 10:1 without affecting the topography feedback. Keywords: bimodal AFM imaging; diblock copolymer; polybutadiene

• ., Santa Barbara, CA) extended with an external setup for bimodal AFM [7][8]. The system was equipped with a Signal Access Module and special circuitry to access the deflection signals directly at the segmented photodiode, as shown in Figure 1. A digital function generator (33220A; Agilent Technologies Inc

• , Germany) with a nominal fundamental resonance of 130 kHz and a nominal flexural stiffness of 30 N/m. A 60 nm thick film of SB diblock copolymer (MW(PS) = 13600 g/mol; MW(PB) = 33700 g/mol) was prepared as a test specimen for bimodal AFM. SB is a diblock copolymer with a polydispersity of Mw/Mn = 1.03

Theoretical study of the frequency shift in bimodal FM-AFM by fractional calculus

• Elena T. Herruzo and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2012, 3, 198–206, doi:10.3762/bjnano.3.22

• Lennard-Jones and Derjaguin–Muller–Toporov forces. Keywords: AFM; atomic force microscopy; bimodal AFM; frequency shift; integral calculus applications; Introduction Since the invention of the atomic force microscope (AFM) [1], numerous AFM studies have been pursued in order to extract information from

• modulus of samples in air [14] and liquids [29][30][31]. Bimodal AFM [32][33] is a force-microscopy method that allows quantitative mapping of the sample properties (Figure 1). Bimodal AFM operates by exciting simultaneously the cantilever at its first and second flexural resonances. The technique

• and dissipation of the second mode in bimodal FM-AFM. Experimental measurements have shown the ability of bimodal AFM to measure a variety of interactions, from electrostatic to magnetic or mechanical, both in ultrahigh vacuum [36][37][38], air [33][34][39][40][41] and liquids [15][18][19