Mechanical Diode-Based Ultrasonic Atomic Force Microscopies

Cuberes, M. Teresa

doi:10.1007/978-3-540-85037-3_3

Cited by 7 publications

(8 citation statements)

References 79 publications

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“…The ultrasonic vibrations applied (~2 MHz) are well above the resonance frequency of CM cantilevers (tens of kHz); hence the cantilever is not be able to linearly follow the surface vibration because of its inertia [50]. If the ultrasonic excitation amplitude is sufficiently high, the tip-sample distance is modulated within the nonlinear tip-sample force interaction regime and the cantilever experiences of an additional static force [51]. This static force causes an additional deflection to the cantilever (UFM signal) with a magnitude that depends on the details of the tip-sample interaction force, i.e.…”

Section: Scanning Probe Microscopies Characterizations Of Organic Filmsmentioning

confidence: 99%

Self-organization of complete organic monolayers via sequential post-deposition annealing

Chiodini

D’Avino

Muccioli

et al. 2020

Progress in Organic Coatings

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Organic molecular beam deposition has been used to surpass the chemical approach commonly adopted for coating SiOx surfaces, obtaining a smooth and uniform monomolecular layer of sexithiophene that fully covers the SiOx surface on the centimetre length scale. This result has been achieved by submitting sexithiophene sub-monolayer films grown at different substrate temperatures to a post-deposition annealing process.Through Scanning Probe Microscopy techniques, morphological, tribological and mechanical measurements have highlighted the existence of face-on molecular aggregates on the SiOx surface and their re-organization by means of a post-annealing process.Atomistic molecular dynamics simulations complement experimental observations, shedding light on the microscopic aspects of molecular diffusion and aggregates reorganization. Exploiting the molecular reorganization upon post-annealing, almost perfect 6T monolayers were grown through a sequence of deposition and annealing steps.This preparation technique represents a new route for changing surface properties by using high controlled monomolecular layers.

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Section: Scanning Probe Microscopies Characterizations Of Organic Filmsmentioning

confidence: 99%

Self-organization of complete organic monolayers via sequential post-deposition annealing

Chiodini

D’Avino

Muccioli

et al. 2020

Progress in Organic Coatings

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“…To implement UFM, a standard commercial AFM (NANOTEC) was appropriately modified [2,4]. Data acquisition and analysis were carried out using the WSxM software [24].…”

Section: -Materials and Methodsmentioning

confidence: 99%

“…Ultrasonic Force Microscopy (UFM) is a powerful technique to investigate the elastic and adhesive response of materials on the nanoscale [1,2]. The procedure is capable to provide material contrast in both soft and hard samples, bringing additional advantages when compared with other Scanning Probe Microscopy (SPM) approaches [3][4][5][6].…”

Section: -Introductionmentioning

confidence: 99%

“…Due to the addition of STO, the PVA samples, transparent in pure form (in the absence of nanoparticles), acquired an opaque white color. Shapes of ≈ 1x1 cm2 were cut from the films, mounted on an appropriate sample holder, and used for the AFM/UFM measurements.To implement UFM, a standard commercial AFM (NANOTEC) was appropriately modified [2,4]. Data acquisition and analysis were carried out using the WSxM software [24].…”

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confidence: 99%

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Ultrasonic force microscopy on poly(vinyl alcohol)/SrTiO3 nano-perovskites hybrid films

et al. 2014

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Atomic Force Microscopy (AFM) and Ultrasonic Force Microscopy (UFM) have been applied to the characterization of composite samples formed by SrTiO3 (STO) nanoparticles (NPs) and polyvinyl alcohol (PVA). The morphological features of the STO NPs were much better resolved in UFM than in contact-mode AFM topography. For high STO concentrations the individual STO NPs formed nanoclusters, which gathered in microaggregates. The STO aggregates, covered by PVA, exhibited no AFM frictional contrast, but were clearly distinguished from the PVA matrix using UFM. Similar aggregation was observed for NPs in the composite samples than for NPs deposited on top of a flat silicon substrate from a milliQ water solution in the absence of polymer. In the hybrid films, most STO nanoparticles typically presented a lower UFM contrast than the PVA matrix, even though stiffer sample regions such as STO should give rise to a higher UFM contrast. STO NPs with intermediate contrast were characterized by an UFM halo of lower contrast at the PVA/STO interface. The results may be explained by considering that ultrasound is effectively damped on the nanometer scale at PVA/ STO interfaces. According to our data, the nanoscale ultrasonic response at the PVA/STO interface plays a fundamental role in the UFM image contrast.KEYWORDS. Atomic Force Microscopy. Ultrasonic Force Microscopy. Poly(vinyl alcohol). Stroncium Titanate. Nanoparticles. Nanocomposites. 1-IntroductionUltrasonic Force Microscopy (UFM) is a powerful technique to investigate the elastic and adhesive response of materials on the nanoscale [1,2]. The procedure is capable to provide material contrast in both soft and hard samples, bringing additional advantages when compared with other Scanning Probe Microscopy (SPM) approaches [3][4][5][6]. Here, UFM is applied to the characterization of composite samples formed by SrTiO3 (STO) nanoparticles (NP) and poly(vinyl alcohol) (PVA). We intend to further explore the capability of the technique to provide subsurface information, to characterize the nanostructures formed by STO NP in the PVA hybrid films, and to gain inside into the mechanisms of ultrasound propagation on the nanoscale and the origin of the UFM contrast.The insertion of ceramics nanoparticles into polymer matrix has led to the generation of novel hybrid materials with improved electrical and thermo-mechanical properties. In titanate-polymer composites, the titanates contribute with a high capacitance, and the polymers are typically easy to process. Hence, the composite films appear very attractive for the fabrication of integrated circuits [7,8]. Composites of STO with polymeric materials have been considered for microwave applications [9,10]. The dielectric properties of PVA mixed with PbTiO3 show promise for their application as supercapacitors and humidity sensors [11]. STO nanoparticles are being tested for the development of thin film transistors [8], batteries [12], photodiodes [13], and solar cells [14]. Also, they may exhibit photocatalytic activity [15][16...

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“…To this purpose, a series of physico-chemical techniques [ 6 ] such as X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and Fourier-transformed infrared spectroscopy (FT-IR) have been applied to the films’ characterization. Contact-angle studies have also been performed, and particular attention has been devoted to the investigation of the films using atomic force microscopy (AFM)-based procedures, including ultrasonic force microscopy (UFM), which is a relatively new technique, extremely powerful for mapping surface and subsurface stiffness inhomogeneities [ 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Nanostructural Arrangements and Surface Morphology on Ureasil-Polyether Films Loaded with Dexamethasone Acetate

et al. 2021

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Ureasil-Poly(ethylene oxide) (ureasil-PEO500) and ureasil-Poly(propylene oxide) (u-PPO400) films, unloaded and loaded with dexamethasone acetate (DMA), have been investigated by carrying out atomic force microscopy (AFM), ultrasonic force microscopy (UFM), contact-angle, and drug release experiments. In addition, X-ray diffraction, small angle X-ray scattering, and infrared spectroscopy have provided essential information to understand the films’ structural organization. Our results reveal that while in u-PEO500 DMA occupies sites near the ether oxygen and remains absent from the film surface, in u-PPO400 new crystalline phases are formed when DMA is loaded, which show up as ~30–100 nm in diameter rounded clusters aligned along a well-defined direction, presumably related to the one defined by the characteristic polymer ropes distinguished on the surface of the unloaded u-POP film; occasionally, larger needle-shaped DMA crystals are also observed. UFM reveals that in the unloaded u-PPO matrix the polymer ropes are made up of strands, which in turn consist of aligned ~180 nm in diameter stiffer rounded clusters possibly formed by siloxane-node aggregates; the new crystalline phases may grow in-between the strands when the drug is loaded. The results illustrate the potential of AFM-based procedures, in combination with additional physico-chemical techniques, to picture the nanostructural arrangements in polymer matrices intended for drug delivery.

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Mechanical Diode-Based Ultrasonic Atomic Force Microscopies

Cited by 7 publications

References 79 publications

Self-organization of complete organic monolayers via sequential post-deposition annealing

Self-organization of complete organic monolayers via sequential post-deposition annealing

Ultrasonic force microscopy on poly(vinyl alcohol)/SrTiO3 nano-perovskites hybrid films

Nanostructural Arrangements and Surface Morphology on Ureasil-Polyether Films Loaded with Dexamethasone Acetate

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