Imaging of conductive filler networks in heterogeneous materials by scanning Kelvin microscopy

Prasse, Torsten; Ivankov, A. F.; Sandler, Jan K.W.; Schulte, Karl; Bauhofer, W.

doi:10.1002/app.2197

Cited by 16 publications

(13 citation statements)

References 14 publications

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“…When the KPFM servo is turned on (see figure 1(b)), it is possible to map the local surface contact potential difference on the PI-SWNTs film in figure 2(h). SWNTs can be distinguished by appearing brighter, with higher [16,20,47]. In addition, from the amplitude response of the electrostatic force at 2ω elec (see equation (2)), ∂C/∂d can be measured and mapped as in figure 2(i).…”

Section: Understanding Single-pass Kpfmmentioning

confidence: 99%

“…It has also been applied to identify dissimilar components in heterogeneous materials [18], and to study the dynamic variation of the local work function at the nanoscale in a poly (3,4-ethylenedioxypyrrole)/carbon nanotube composite [19]. At the microscopic scale, Kelvin probe microscopy (not AFM based) has been used to reveal the distribution of induced conductive networks of carbon black (CB) and CNTs in epoxy polymers [20]. Given the recent surge of interest in the use of dynamic electrical AFM techniques for nanocomposite characterization, there is a strong need to understand the fundamentals of image formation in these techniques, their spatial and depth resolution, and their experimental advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

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Sub-surface imaging of carbon nanotube–polymer composites using dynamic AFM methods

et al. 2013

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High-resolution sub-surface imaging of carbon nanotube (CNT) networks within polymer nanocomposites is demonstrated through electrical characterization techniques based on dynamic atomic force microscopy (AFM). We compare three techniques implemented in the single-pass configuration: DC-biased amplitude modulated AFM (AM-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM) in terms of the physics of sub-surface image formation and experimental robustness. The methods were applied to study the dispersion of sub-surface networks of single-walled nanotubes (SWNTs) in a polyimide (PI) matrix. We conclude that among these methods, the KPFM channel, which measures the capacitance gradient (∂C/∂d) at the second harmonic of electrical excitation, is the best channel to obtain high-contrast images of the CNT network embedded in the polymer matrix, without the influence of surface conditions. Additionally, we propose an analysis of the ∂C/∂d images as a tool to characterize the dispersion and connectivity of the CNTs. Through the analysis we demonstrate that these AFM-based sub-surface methods probe sufficiently deep within the SWNT composites, to resolve clustered networks that likely play a role in conductivity percolation. This opens up the possibility of dynamic AFM-based characterization of sub-surface dispersion and connectivity in nanostructured composites, two critical parameters for nanocomposite applications in sensors and energy storage devices.

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Section: Understanding Single-pass Kpfmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sub-surface imaging of carbon nanotube–polymer composites using dynamic AFM methods

et al. 2013

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“…Moreover, Breuer and Sundararaj [29] report difficulty in implementing electron microscopy due to issues with regard to sample preparation and the lack of polymer/ CNT contrast. They list other methods, such as magnetic force microscopy (MFM) which exploits the interaction between the CNTs and the applied magnetic field, thus allowing direct visualisation of the polymer embedded CNTs [29] and scanning Kelvin microscopy which employs an oscillating probe to determine the conductivity distribution in heterogeneous materials such as the conducting CNTs in the insulating polymer matrix [98]. Yet another characterisation method that has been used is X-ray diffraction (XRD), as employed by Dror et al [18].…”

Section: Synthesis Of Polymer Nanocomposite Fibers By Electrospinningmentioning

confidence: 99%

Electrospinning carbon nanotube polymer composite nanofibers

Yeo

Friend

2006

Journal of Experimental Nanoscience

137

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The unique and exceptional physical properties of carbon nanotubes have inspired their use as a filler within a polymeric matrix to produce carbon nanotube polymer composites with enhanced mechanical, thermal and electrical properties. A powerful method of synthesising nanofibers comprising these polymer composites is electrospinning, which utilises an applied electric stress to draw out a thin nanometer-dimension fiber from the tip of a sharp conical meniscus. The focussing of the flow due to converging streamlines at the cone vertex then ensures alignment of the carbon nanotubes along the fiber axis, thus enabling the anisotropic properties of the nanotubes to be exploited. We consider the work that has been carried out to date on various aspects encompassing preprocessing, synthesis and characterisation of these electrospun polymer composite nanofibers as well as the governing mechanisms and associated properties of such fibers. Particular attention is also dedicated to the theoretical modelling of these fiber systems, in particular to the electrohydrodynamic modelling of electrospinning polymer jets.

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“…Among the electric techniques, EFM is mainly used for the characterization of the local electronic and dielectric properties of conducting, insulating and semiconducting materials (Jespersen & Nygård, 2007;Kader, Choi, Lee, & Nah, 2005;Prasse, Ivankov, Sandler, Schulte, & Bauhofer, 2001). Kelvin probe force microscopy (KPFM) is another electric SPM technique widely used for the measurement of the electric surface characteristics of materials.…”

Section: Characterization Of Nanoparticles and Nanosystemsmentioning

confidence: 99%

Identification of nanoparticles and nanosystems in biological matrices with scanning probe microscopy

Angeloni

Reggente

Passeri

et al. 2018

WIREs Nanomed Nanobiotechnol

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Identification of nanoparticles and nanosystems into cells and biological matrices is a hot research topic in nanobiotechnologies. Because of their capability to map physical properties (mechanical, electric, magnetic, chemical, or optical), several scanning probe microscopy based techniques have been proposed for the subsurface detection of nanomaterials in biological systems. In particular, atomic force microscopy (AFM) can be used to reveal stiff nanoparticles in cells and other soft biomaterials by probing the sample mechanical properties through the acquisition of local indentation curves or through the combination of ultrasound-based methods, like contact resonance AFM (CR-AFM) or scanning near field ultrasound holography. Magnetic force microscopy can detect magnetic nanoparticles and other magnetic (bio)materials in nonmagnetic biological samples, while electric force microscopy, conductive AFM, and Kelvin probe force microscopy can reveal buried nanomaterials on the basis of the differences between their electric properties and those of the surrounding matrices. Finally, scanning near field optical microscopy and tip-enhanced Raman spectroscopy can visualize buried nanostructures on the basis of their optical and chemical properties. Despite at a still early stage, these methods are promising for detection of nanomaterials in biological systems as they could be truly noninvasive, would not require destructive and time-consuming specific sample preparation, could be performed in vitro, on alive samples and in water or physiological environment, and by continuously imaging the same sample could be used to dynamically monitor the diffusion paths and interaction mechanisms of nanomaterials into cells and biological systems. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

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Imaging of conductive filler networks in heterogeneous materials by scanning Kelvin microscopy

Cited by 16 publications

References 14 publications

Sub-surface imaging of carbon nanotube–polymer composites using dynamic AFM methods

Sub-surface imaging of carbon nanotube–polymer composites using dynamic AFM methods

Electrospinning carbon nanotube polymer composite nanofibers

Identification of nanoparticles and nanosystems in biological matrices with scanning probe microscopy

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