Mechanical Property Mapping at the Nanoscale Using PeakForce QNM Scanning Probe Technique

Pittenger, Bede; Erina, N. A.; Su, Chanmin

doi:10.1007/978-94-007-6919-9_2

Cited by 198 publications

(263 citation statements)

References 17 publications

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“…The calibration process was performed using the absolute method and was checked through the relative method as recommended by the supplier. 15 UV-vis spectra were obtained using a Perkin-Elmer Lambda 6 UV/Vis spectrophotometer. X-ray diffraction studies were Current density-voltage (J-V) measurements were carried out using a Keithley 2400 source unit.…”

Section: Photoactive Film Preparationmentioning

confidence: 99%

Air processed P3HT:PCBM photovoltaic cells: Morphology correlation to annealing, degradation, and recovery

Bhattacharya

Moore

et al. 2014

J Polym Sci B Polym Phys

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Systematically varied annealing, encapsulation, and solvent vapor treatments are conducted to produce stable OPV devices with controlled film morphology and high performance when produced in air. Active layer films are analyzed by AFM, nanomechanical mapping, UV-vis spectroscopy, and XRD. Devices prepared with isopropanol solvent vapor annealing (SVA) combined with thermal annealing (TA) show the highest environmental resistance and performance. Such devices yield average PCE of 3.3%, with stability to atmospheric exposure of up to 60 min prior to encapsulation. Encapsulated devices exposed to the laboratory environment for 30 days exhibit a decrease in PCE of 15%. On application of a second TA step PCE is recovered to over 90% of the original value. The unprecedented air stability of the cells is attributed to the formation of an active layer with a stable, favorable morphology during the SVA process, which is associated with lower oxygen content films.

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Section: Photoactive Film Preparationmentioning

confidence: 99%

Air processed P3HT:PCBM photovoltaic cells: Morphology correlation to annealing, degradation, and recovery

Bhattacharya

Moore

et al. 2014

J Polym Sci B Polym Phys

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“…Force distance curves (force curves) are acquired to obtain information about mechanical properties and interparticulate interactions ( Fig. 2) (Pittenger et al, 2010). Initially, the movement of the z-piezo and the deflection of the cantilever are recorded over time.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…Highly developed software programmes allow the conversion of the measured deflection into force ( Fig. 2a and b) (Pittenger et al, 2010). For interpretation purposes, the force is then plotted against the separation between the tip of the probe and the sample surface which is derived from the position of the z-piezo ( Fig.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

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Characterisation of dry powder inhaler formulations using atomic force microscopy

Weiss

McLoughlin

Cathcart

2015

International Journal of Pharmaceutics

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A B S T R A C TInhalation formulations are a popular way of treating the symptoms of respiratory diseases. The active pharmaceutical ingredient (API) is delivered directly to the site of action within the deep lung using an inhalation device such as the dry powder inhaler (DPI).The performance of the formulation and the efficiency of the treatment depend on a number of factors including the forces acting between the components. In DPI formulations these forces are dominated by interparticulate interactions. Research has shown that adhesive and cohesive forces depend on a number of particulate properties such as size, surface roughness, crystallinity, surface energetics and combinations of these. With traditional methods the impact of particulate properties on interparticulate forces could be evaluated by examining the bulk properties. Atomic force microscopy (AFM), however, enables the determination of local surface characteristics and the direct measurement of interparticulate forces using the colloidal probe technique. AFM is considered extremely useful for evaluating the surface topography of a substrate (an API or carrier particle) and even allows the identification of crystal faces, defects and polymorphs from high-resolution images. Additionally, information is given about local mechanical properties of the particles and changes in surface composition and energetics. The assessment of attractive forces between two bodies is possible by using colloidal probe AFM.This review article summarises the application of AFM in DPI formulations while specifically focussing on the colloidal probe technique and the evaluation of interparticulate forces.2015 Elsevier B.V. All rights reserved.

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“…As a remedy nonresonant tapping mode techniques are used. Thus, AFM with low frequency excitation compared to the fundamental natural frequency of the cantilever is used, for instance, in the pulsed-force mode AFM [11] and the peak-force AFM [12]. Indeed, the low frequency excitation leads to lower the tapping force causing limited tip-sample contact areas and minimizing the loss of resolution.…”

Section: Introductionmentioning

confidence: 99%

Effects of a slow harmonic displacement on an Atomic Force Microscope system under Lennard-Jones forces

2016

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Abstract. We focus in this paper on the modeling and dynamical analysis of a tapping mode atomic force microscopy (AFM). The microbeam is subjected to a low frequency harmonic displacement of its base and to the Lennard-Jones (LJ) forces at its free end. Static and modal analysis are performed for various gaps between the tip of the microbeam and a sample. The Galerkin method is employed to reduce the equations of motion to a fast-slow dynamical system. We show that the dynamics of the AFM system is governed by the contact and the noncontact invariant slow manifolds. The tapping mode is triggered via two saddle-node bifurcations of these manifolds. Moreover, the contact time is computed and the effects of the base motion amplitude and the initial gap are discussed.

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Mechanical Property Mapping at the Nanoscale Using PeakForce QNM Scanning Probe Technique

Cited by 198 publications

References 17 publications

Air processed P3HT:PCBM photovoltaic cells: Morphology correlation to annealing, degradation, and recovery

Air processed P3HT:PCBM photovoltaic cells: Morphology correlation to annealing, degradation, and recovery

Characterisation of dry powder inhaler formulations using atomic force microscopy

Effects of a slow harmonic displacement on an Atomic Force Microscope system under Lennard-Jones forces

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