Miscibility and Phase Separation in PMMA/SAN Blends Investigated by Nanoscale AFM-IR

The miscibility and phase separation of poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile (SAN) have already been investigated using various methods. However, these methods have limitations that often result in inconsistent characterization. Consequently, the reasons for the dependence of miscibility on composition as well as on processing temperature have not yet been proved. The phase separation of PMMA/SAN blends was therefore investigated for the first time using a novel technique, nanoscale AFM-IR. It couples nanoscale atomic force microscopy (AFM) with infrared (IR) spectroscopy. Therefore, the phase morphology can be chemically identified and precisely classified within the nm-regime. The PMMA/SAN blends, on the other hand, were analyzed of their changes in morphology under different thermal treatments. It was possible to visualize and define the phase separation, as well as dependence of the miscibility on the mixing ratio. In the miscible domain, no two individual phases could be detected down to the nanometer range. It was shown that with increasing temperature, the morphology changes and two different phases are formed, where the phase boundaries can be sharply defined. The onset of these changes could be identified at temperatures of about 100 °C.

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Effects of nanoparticles on phase morphology in thin films of phase-separated diblock copolymers

Powder Diffraction ◽

10.1017/s0885715616000762 ◽

2017 ◽

Vol 32 (S1) ◽

pp. S141-S150

Author(s):

Dieter Jehnichen ◽

Doris Pospiech ◽

Peter Friedel ◽

Andriy Horechyy ◽

Andreas Korwitz ◽

...

Keyword(s):

Thin Films ◽

Atomic Force Microscopy ◽

Phase Separation ◽

Diblock Copolymers ◽

Force Microscopy ◽

Atomic Force ◽

Gold Silver ◽

Lateral Distance ◽

Morphology Changes ◽

Periodic Nanostructure

This study investigates the morphology changes in thin diblock copolymer (DiBCP) films occurring in the interaction with modified nanoparticles (NPs). Magnetite (Fe3O4) and silica (SiOx) were prepared and used. Poly(pentyl methacrylate-b-methyl methacrylate) (PPMA-b-PMMA) (70/30 mol mol−1, hcp cylinders of the PMMA phase) DiBCP were employed to prepare thin films having thicknesses to realize standing cylinders in pure DiBCP films. The investigations aimed at two topics: (1) morphology after controlled incorporation of organo-modified NP (gold, silver, Fe3O4, SiOx) and (2) additional solvent vapour annealing (SVA) with tetrahydrofuran (and chloroform for comparison). The laterally ordered morphology in thin films was examined by GISAXS and atomic force microscopy. Keeping the same type of morphology in nanocomposites, the dimensions of the periodic nanostructure altered depending on type and amount of incorporated NP. It was found that SiOx clusters enlarge the lateral distance of the PMMA cylinders, whereas metallic NPs reduce this parameter. Applying SVA improves the phase separation slightly, whereas lateral distances were kept constant or were reduced a little. Switching of domain orientation upon SVA could not be detected in the presence of NPs located at the polymer/substrate interface.

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High resolution nanoscale chemical analysis of bitumen surface microstructures

Scientific Reports ◽

10.1038/s41598-021-92835-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ayse N. Koyun ◽

Julia Zakel ◽

Sven Kayser ◽

Hartmut Stadler ◽

Frank N. Keutsch ◽

...

Keyword(s):

Secondary Ion Mass Spectrometry ◽

Force Microscopy ◽

Photo Oxidation ◽

Atomic Force ◽

Para Phase ◽

Key Sites ◽

Respective Surface ◽

Surface Domains ◽

Surface Microstructures ◽

First Time

AbstractSurface microstructures of bitumen are key sites in atmospheric photo-oxidation leading to changes in the mechanical properties and finally resulting in cracking and rutting of the material. Investigations at the nanoscale remain challenging. Conventional combination of optical microscopy and spectroscopy cannot resolve the submicrostructures due to the Abbe restriction. For the first time, we report here respective surface domains, namely catana, peri and para phases, correlated to distinct molecules using combinations of atomic force microscopy with infrared spectroscopy and with correlative time of flight—secondary ion mass spectrometry. Chemical heterogeneities on the surface lead to selective oxidation due to their varying susceptibility to photo-oxidation. It was found, that highly oxidized compounds, are preferentially situated in the para phase, which are mainly asphaltenes, emphasising their high oxidizability. This is an impressive example how chemical visualization allows elucidation of the submicrostructures and explains their response to reactive oxygen species from the atmosphere.

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Preparation and Characterization of Chitosan-Casein Phosphopeptides Biocomposite Coatings on the Medical Titanium Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.480-481.1065 ◽

2011 ◽

Vol 480-481 ◽

pp. 1065-1069

Author(s):

Bin Liu ◽

Lin Wang ◽

Yin Zhong Bu ◽

Sheng Rong Yang ◽

Jin Qing Wang

Keyword(s):

Photoelectron Spectroscopy ◽

Attenuated Total Reflectance ◽

Ti Alloy ◽

Force Microscopy ◽

Implant Materials ◽

Atomic Force ◽

Casein Phosphopeptides ◽

Potential Applications ◽

First Time

Titanium (Ti) and its alloys have been applied in orthopedics as one of the most popular biomedical metallic implant materials. In this work, to enhance the bioactivity, the surface of Ti alloy pre-modified by silane coupling agent and glutaraldehyde was covalently grafted with chitosan (CS) via biochemical multistep self-assembled method. Then, for the first time, the achieved surface was further immobilized with casein phosphopeptides (CPP), which are one group of bioactive peptides released from caseins in the digestive tract and can facilitate the calcium adsorption and usage, to form CS-CPP biocomposite coatings. The structure and composition of the fabricated coatings were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). As the experimental results indicated, multi-step assembly was successfully performed, and the CS and CPP were assembled onto the Ti alloy surface orderly. It is anticipated that the Ti alloys modified by CS-CPP biocomposite coatings will find potential applications as implant materials in biomedical fields.

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Microwave Spectroscopic Detection of Human Hsp70 Protein on Annealed Gold Nanostructures on ITO Glass Strips

Biosensors ◽

10.3390/bios8040118 ◽

2018 ◽

Vol 8 (4) ◽

pp. 118

Author(s):

Rodica Ionescu ◽

Raphael Selon ◽

Nicolas Pocholle ◽

Lan Zhou ◽

Anna Rumyantseva ◽

...

Keyword(s):

Indium Tin Oxide ◽

Stress Disorders ◽

Force Microscopy ◽

Glass Substrates ◽

Conductive Glass ◽

Hsp70 Protein ◽

Atomic Force ◽

Ito Glass ◽

First Time ◽

Human Heat Shock Protein

Conductive indium-tin oxide (ITO) and non-conductive glass substrates were successfully modified with embedded gold nanoparticles (AuNPs) formed by controlled thermal annealing at 550 °C for 8 h in a preselected oven. The authors characterized the formation of AuNPs using two microscopic techniques: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analytical performances of the nanostructured-glasses were compared regarding biosensing of Hsp70, an ATP-driven molecular chaperone. In this work, the human heat-shock protein (Hsp70), was chosen as a model biomarker of body stress disorders for microwave spectroscopic investigations. It was found that microwave screening at 4 GHz allowed for the first time the detection of 12 ng/µL/cm2 of Hsp70.

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Marrying Medicine and Materials: Artemisinin (Qinghaosu) Particle is Soft Enough for Scratching Hard SiC Wafer in Water

ScienceOpen Research ◽

10.14293/s2199-1006.1.sor-matsci.amnmzs.v1 ◽

2016 ◽

Author(s):

Yu-rong Zhu ◽

Dan Zhang ◽

Yang Gan ◽

Fei-hu Zhang

Keyword(s):

Pure Water ◽

High Hardness ◽

Underlying Mechanism ◽

Molecular Solids ◽

High Brightness ◽

Force Microscopy ◽

Atomic Force ◽

Chemical Inertness ◽

Sic Wafer ◽

First Time

<p>Silicon carbide (SiC) single crystals, along with sapphire and silicon, are one of most important substrates for high-brightness LED fabrications. Owing to extremely high hardness (Mohs’ scale of 9.5) and chemical inertness, the polishing rate of SiC with conventional chemical mechanical polishing (CMP) methods is not high, and surface scratches are also inevitable because of using slurry containing hard abrasives such as silica particles. Here artemisinin (Qinghaosu) crystals, very soft molecular solids, were found, for the first time to the best of our knowledge, to effectively polish SiC wafers even in pure water as demonstrated by proof-of-concept scratching experiments using atomic force microscopy (AFM). The underlying mechanism is attributed to activated oxidation of SiC by mechanically released reactive ·OH free radicals from the endoperoxide bridges. The preliminary results reported here have important implications for developing novel alternative green and scratch-free polishing methods for hard-brittle substrates including SiC and others.</p>

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Flotation Behavior of Diatomite and Albite Using Dodecylamine as a Collector

Minerals ◽

10.3390/min8090371 ◽

2018 ◽

Vol 8 (9) ◽

pp. 371 ◽

Cited By ~ 1

Author(s):

Ying Gao ◽

Yuexin Han ◽

Wenbo Li

Keyword(s):

Unit Area ◽

Alkaline Ph ◽

Force Microscopy ◽

Atomic Force ◽

Mineral Flotation ◽

Alkaline Conditions ◽

Negative Surface ◽

Negative Surface Charge ◽

Ph Range ◽

First Time

The flotation behaviors of diatomite and albite using dodecylamine (DDA) as a collector were investigated and compared. The pure mineral flotation results indicate that the flotability difference between albite and diatomite is above 87% at pH 5.5 to 10.5. The recovery of albite improves with increasing DDA dosage at pH 5.5 to 10.5. In the same pH range, diatomite has weaker flotability than albite, particularly in alkaline pH pulp. Zeta potential measurements indicate that diatomite has a higher negative surface charge than albite at pH 7 to 12, DDA interacts strongly with albite and weakly with diatomite. Thus, DDA preferentially absorbs on albite surface rather than diatomite under alkaline conditions. Fourier transform infrared spectra (FTIR) indicate that the amount of DDA adsorbed to albite is greater than that adsorbed to diatomite, under the same conditions. The adsorption of DDA on the surface of diatomite is investigated by using atomic force microscopy (AFM) for the first time. The adsorption of the collector DDA on the surface of albite per unit area is greater than that on diatomite. This accounts for the lower recovery of diatomite than that of albite.

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Formation of Sub-100 NM GE Wires on Si by E-Beam Evaporation/Lithography

MRS Proceedings ◽

10.1557/proc-380-105 ◽

1995 ◽

Vol 380 ◽

Cited By ~ 1

Author(s):

C. Deng ◽

J. C. Wu ◽

C. J. Barbero ◽

T. W. Sigmon ◽

M. N. Wybourne

Keyword(s):

Cross Section ◽

Focused Ion Beam ◽

Ion Beam ◽

Si Substrates ◽

Novel Technique ◽

Atomic Force ◽

Transmission Electron ◽

First Time ◽

Scanning Electron

ABSTRACTA fabrication process for sub-100 nm Ge wires on Si substrates is reported for the first time. Wires with a cross section of 6 × 57 nm2 are demonstrated. The wire structures are analyzed by atomic force (AFM), scanning electron (SEM), and transmission electron microscopy (TEM). Sample preparation for TEM is performed using a novel technique using both pre and in situ deposition of multiple protection layers using a Focused Ion Beam (FIB) micromachining system.

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First identification of nanoparticles on thorax, abdomen and wings of the worker bee Apis dorsata Fabricius

Journal of Apicultural Science ◽

10.1515/jas-2016-0008 ◽

2016 ◽

Vol 60 (1) ◽

pp. 87-96

Author(s):

Atanu Bhattacharyya ◽

Shashidhar Viraktamath ◽

Fani Hatjina ◽

Santanu Bhattacharyya ◽

Bhaktibhavana Rajankar ◽

...

Keyword(s):

Electron Microscopy ◽

Average Diameter ◽

The Body ◽

Apis Dorsata ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Calcium Phosphate Nanoparticles ◽

First Time

Abstract The presence of nanoparticles on the body of the honeybee Apis dorsata Fabricius, was investigated for the first time to better understand the bee’s behaviour. These have been observed by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and confirmed by Atomic Force Microscopy (AFM). Our study clearly denotes that the Indian rock honey bee Apis dorsata possess calcium silicate and calcium phosphate nanoparticles on its body surface of 5-50 nm in diameter. In particular, the nanoparticles on the abdomen and thorax of A. dorsata have an average diameter of about 10 nanometers and they are smaller than those found on wings of the same bees which are about 20 nanometers. The nanoparticles found are different of the ones previously observed on honey bees or other insects. The origin and role of these natural nanoparticles on the body of the Indian rock bee need to be to be further investigated; more research in the subject might raise important aspects in relation to the conservation of these unique pollinators.

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Understanding the Resistive Switching Phenomena of Stacked Al/Al2O3/Al Thin Films from the Dynamics of Conductive Filaments

Complexity ◽

10.1155/2017/8263904 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 4

Author(s):

Joel Molina-Reyes ◽

Luis Hernandez-Martinez

Keyword(s):

Resistive Switching ◽

Atomic Layer ◽

Memory Device ◽

Switching Behavior ◽

Processing Temperature ◽

Force Microscopy ◽

Atomic Force ◽

Layer Deposition ◽

Metal Insulator Metal ◽

Switching Characteristics

We present the resistive switching characteristics of Metal-Insulator-Metal (MIM) devices based on amorphous Al2O3 which is deposited by Atomic Layer Deposition (ALD). A maximum processing temperature for this memory device is 300°C, making it ideal for Back-End-of-Line (BEOL) processing. Although some variations in the forming, set, and reset voltages (VFORM, VSET, and VRESET) are obtained for many of the measured MIM devices (mainly due to roughness variations of the MIM interfaces as observed after atomic-force microscopy analysis), the memristor effect has been obtained after cyclic I-V measurements. These resistive transitions in the metal oxide occur for both bipolar and unipolar conditions, while the IOFF/ION ratio is around 4–6 orders of magnitude and is formed at gate voltages of Vg<4 V. In unipolar mode, a gradual reduction in VSET is observed and is related to combined (a) incomplete dissolution of conductive filaments (made of oxygen vacancies and metal ions) which leaves some residuals and (b) thickening of chemically reduced Al2O3 during localized Joule heating. This is important because, by analyzing the macroscopic resistive switching behavior of this MIM structure, we could indirectly relate it to microscopic and/or nanoscopic phenomena responsible for the physical mechanism upon which most of these devices operate.

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Diverse approaches to the controlled generation of nanotextured surfaces

Pure and Applied Chemistry ◽

10.1351/pac200880081651 ◽

2008 ◽

Vol 80 (8) ◽

pp. 1651-1668

Author(s):

Jeremy J. Ramsden

Keyword(s):

Phase Separation ◽

Molecular Recognition ◽

Recognition Task ◽

Force Microscopy ◽

Irregular Structures ◽

Atomic Force ◽

Powerful Approach ◽

Atomic Precision ◽

Pick And Place ◽

Regular Arrays

Smooth, chemically uniform surfaces are seldom found in nature. Mimicry of natural variegation is a powerful approach for controlling chemical affinity at the nanoscale. Molecular recognition is one of the fundamental concepts underlying the functioning of living cells, and it depends on a particular relationship between the nanoscale, i.e., molecular, variegations of two potentially interacting molecular partners. The primary subject matter of this paper is how to articially generate appropriate nanoscale texture at the surfaces of materials. Excluding "pick and place" chemistry, in which essentially a Maxwellian demon intervenes to place objects with atomic precision, and nowadays achievable through an adaptation of atomic force microscopy, on the grounds that it is too slow to be practicable for fabricating useful quantities of material, three approaches are explored in some detail: (i) "powder", i.e., mixing at least two individually monofunctional (with respect to the ultimate molecular recognition task) precursor components (possibly with secondary functionality enabling them to appropriately self-assemble on a substratum); (ii) mixing polymers with the possibility of phase separation and frustrated phase separation with block copolymers; and (iii) felting. The emphasis is on processes that create more or less irregular structures, rather than regular arrays. The final section deals with the metrology of nanotexture.

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