Conductance Mapping of Proton Exchange Membranes by Current Sensing Atomic Force Microscopy

This paper presents experiments on Nafion® proton exchange membranes and numerical simulations illustrating the trade-offs between the optimization of compositional contrast and the modulation of tip indentation depth in bimodal atomic force microscopy (AFM). We focus on the original bimodal AFM method, which uses amplitude modulation to acquire the topography through the first cantilever eigenmode, and drives a higher eigenmode in open-loop to perform compositional mapping. This method is attractive due to its relative simplicity, robustness and commercial availability. We show that this technique offers the capability to modulate tip indentation depth, in addition to providing sample topography and material property contrast, although there are important competing effects between the optimization of sensitivity and the control of indentation depth, both of which strongly influence the contrast quality. Furthermore, we demonstrate that the two eigenmodes can be highly coupled in practice, especially when highly repulsive imaging conditions are used. Finally, we also offer a comparison with a previously reported trimodal AFM method, where the above competing effects are minimized.

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Electron Transfer through Organic Monolayers Directly Bonded to Silicon Probed by Current Sensing Atomic Force Microscopy: Effect of Chain Length and Applied Force

The Journal of Physical Chemistry B ◽

10.1021/jp049719+ ◽

2004 ◽

Vol 108 (44) ◽

pp. 17129-17135 ◽

Cited By ~ 35

Author(s):

Jianwei Zhao ◽

Kohei Uosaki

Keyword(s):

Atomic Force Microscopy ◽

Electron Transfer ◽

Chain Length ◽

Applied Force ◽

Organic Monolayers ◽

Current Sensing ◽

Force Microscopy ◽

Atomic Force

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Conducting Polymer nanoComposites (CPC): Nanocharacterisation of layer by layer sprayed PMMA-CNT vapour sensors by Atomic force Microscopy in current Sensing Mode (CS-AFM)

MRS Proceedings ◽

10.1557/proc-1143-kk02-06 ◽

2008 ◽

Vol 1143 ◽

Cited By ~ 1

Author(s):

Bijandra Kumar ◽

Mickaël Castro ◽

Jianbo Lu ◽

Jean-François Feller

Keyword(s):

Atomic Force Microscopy ◽

Spray Deposition ◽

Dynamic Mode ◽

Layer By Layer ◽

Initial State ◽

Contact Mode ◽

Current Sensing ◽

Multi Wall Carbon Nanotubes ◽

Force Microscopy ◽

Atomic Force

ABSTRACTOrganic vapour sensors based on poly (methylmethacrylate)-multi-wall carbon nanotubes (PMMA-CNT) conductive polymer nanocomposite (CPC) were developed via layer by layer technique by spray deposition. CPC Sensors were exposed to three different classes of solvents (chloroform, methanol and water) and their chemo-electrical properties were followed as a function of CNTcontent in dynamic mode. Detection time was found to be shorter than that necessary for full recovery of initial state. CNT real three dimensional network has been visualized by Atomic force microscopy in a field assisted intermittent contact mode. More interestingly real conductive network system and electrical ability of CPC have been explored by current-sensing atomic force microscopy (CS-AFM). Realistic effect of voltage on electrical conductivity has been found linear.

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