Atomic force microscopy on polymers and polymer related compounds (original) (raw)
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Determination of nano-roughness of carbon fibers by atomic force microscopy
Journal of Materials Science, 2013
We present a novel approach to determine the surface roughness on varying scales using atomic force microscopy data. The key factor is to find a suitable background correction for the desired scale. Using the example of the surface of sized and unsized high-tenacity carbon fibers, we present an easy method to find backgrounds for widely varying scales and to evaluate respective topography and surface roughness with the same lateral resolution as the microscope itself. The analysis is done by subtracting a tunable background from the respective height data. By choosing an appropriate background to investigate the surface topography of a carbon fiber on a nm-scale, only small nano-structures with a width of around 20 nm remain after the background subtraction. Evaluating the mean roughness R a of these nanostructures, sized carbon fibers show an overall value of around 0.1 nm while unsized carbon fibers a value of around 0.4 nm. Total background corrected height analysis shows an even distribution of these nano-structures along the fibrils of the unsized fibers, whereas for the sized fibers the nano-structures are not present. The presented method allows analysis and visualization of the distribution of nano-structures on a carbon fiber surface for the first time. This feature is used to visualize the distribution of the sizing and can further be used to investigate the influence of different production parameters on the fiber topography or to evaluate the contribution of mechanical interlocking to the interfacial strength.
Indian Journal of Engineering and Materials Sciences
Atomic force microscopy (AFM) is a relatively new technique used for the surface characterization of polymers. It is capable of producing images of a non-conducting polymer surface without any chemical etching or staining. The unique fea-ture of this technique as compared to other microscopy techniques is that we can study the mechanical properties of the polymer surface and it also does not involve the use of electron beam radiation that damages the polymer surface. This paper describes the various applications of atomic force microscopy like evaluation of mechanical properties, determining the chemical composition, studying photo-oxidative degradation of polymers, measuring the surface adhesion forces, studying the thermal phase transitions in polymers and determining the molecular weight and polydispersity index of polymer brushes. These applications have been elucidated with suitable examples. IPC Code: G01N13/16 The chemical properties and topography of polymer surfaces determi...
Recent Applications of Advanced Atomic Force Microscopy in Polymer Science: A Review
Polymers, 2020
Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. This paper reviews some recent progress in the application of AFM and AFM-IR in polymer science. We describe the principle of AFM-IR and the recent improvements to enhance its resolution. We also discuss the latest progress in the use of AFM-IR as a super-resolution correlated scanned-probe infrared spectroscopy for the chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers, and biopolymers. To highlight the advantages of AFM-IR, we report several results in studying the crystallization of both miscible and immiscible blends as well as polymer aging. Finally, we demonstrate how this novel technique can be used to determine phase separation, spherulitic str...
Recent Progressive Use of Advanced Atomic Force Microscopy in Polymer Science: A Review
2020
Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. In this perspective paper, we review recent progress in the use of AFM-IR in polymer science. We describe first the principle of AFM-IR and the recent improvements to enhance its resolution. We discuss then the last progress in the use of AFM-IR as a super-resolution correlated scanned-probe IR spectroscopy for chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers and biopolymers. To highlight the advantages of AFM-IR, we report here several results in studying crystallization of both miscible and immiscible blends as well as polymer aging. Then, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure and c...
Quantitative Nano-characterization of Polymers Using Atomic Force Microscopy
Chimia, 2017
The present article offers an overview on the use of atomic force microscopy (AFM) to characterize the nanomechanical properties of polymers. AFM imaging reveals the conformations of polymer molecules at solid- liquid interfaces. In particular, for polyelectrolytes, the effect of ionic strength on the conformations of molecules can be studied. Examination of force versus extension profiles obtained using AFM-based single molecule force spectroscopy gives information on the entropic and enthalpic elasticities in pN to nN force range. In addition, single molecule force spectroscopy can be used to trigger chemical reactions and transitions at the molecular level when force-sensitive chemical units are embedded in a polymer backbone.
Atomic Force Microscopy of Polymer Coated Graphitic Carbon Surfaces
Soft Materials, 2014
A modified AFM technique was used to measure interactions between graphitic carbon black particles and, hence, compare effectiveness of dispersants for stable dispersions. The carbon black dispersions were prepared in water using three polymeric dispersants Triton X100, Triton X405 and Lugalvan BNO12. The surfactants were selected based on a previous study with PE/F103 without aromatic ring. That surfactant had attractive interactions emphasizing need for aromatic ring in anchoring group. Attractive interactions between surfaces were observed in water and in absence of polymers. Lack of any attractive interactions in the presence of polymers proved that the selected dispersants are effective stabilizers.
Tensile tests were performed on carbon nanofibers in situ a transmission electron microscope (TEM) using a microelectromechanical system (MEMS) tensile testing device. The carbon nanofibers tested in this study were produced via the electrospinning of polyacrylonitrile (PAN) into fibers, which are subsequently stabilized in an oxygen environment at 270°C and carbonized in nitrogen at 800°C. To investigate the relationship between the fiber molecular structure, diameter, and mechanical properties, nanofibers with diameters ranging from $100 to 300 nm were mounted onto a MEMS device using nanomanipulation inside the chamber of a Scanning Electron Microscope, and subsequently tested in tension in situ a TEM. The results show the dependence of strength and modulus on diameter, with a maximum modulus of 262 GPa and strength of 7.3 GPa measured for a 108 nm diameter fiber. In particular, through TEM evaluation of the structure of each individual nanofiber immediately prior to testing, we elucidate a dependence of mechanical properties on the molecular orientation of the graphitic structure: the strength and stiffness of the fibers increases with a higher degree of orientation of the 0 0 2 graphitic planes along the fiber axis, which coincides with decreasing fiber diameter.
Feature Article: Atomic Force Microscopy: Applications in the Plastics Industry
Polymer News, 2005
The relatively recent invention of atomic force microscopy (AFM) in the early 1980s has proven to be a boon for the characterization of polymers in the plastics industry. Polymer surface morphology can be characterized at high magnification and resolution by AFM, which is an excellent complimentary technique to the electron microscopy (EM) techniques, such as scanning electron (SEM) and transmission electron microscopy (TEM). AFM has rapidly increased in applications to polymer characterization and has distinguished itself as a primary technique for such characterization. AFM has been especially effective in the characterization of all types of fabricated polymer articles, such as films, injection and blow moldings, etc., and has proven especially effective for characterizing multi-phase polymer systems. One aspect of the AFM technique, in comparison to the electron microscopies, is the ease of sample preparation. AFM requires little or no sample preparation and preserves sample structure, whereas SEM and TEM, typically, require much more sample preparation, which often destroys or modifies sample structure in the process. AFM has the attribute of directness of observation and, therefore, reveals structural features of natural surfaces or cross-sections of fabricated polymer articles, which are often difficult to observe by the electron microscopies, due to the necessity of more extensive sample preparation. The AFM technique also has the advantage of independently providing information both on the in-plane, as well as the height, features of a surface. This article describes aspects of the AFM technique relative to basic principles, sample preparation, morphology of polymers, comparison to the EM techniques and characterization of fabricated plastics.
Atomic Force Microscopy Characterization of Carbon Nanotubes
Journal of Physics: Conference Series, 2007
Cellulose nanocrystals (CNCs) are gaining interest as a "green" nanomaterial with superior mechanical and chemical properties for high-performance nanocomposite materials; however, there is a lack of accurate material property characterization of individual CNCs. Here, a detailed study of the topography, elastic and adhesive properties of individual wood-derived CNCs is performed using atomic force microscopy (AFM). AFM experiments involving high-resolution dynamic mode imaging and jump-mode measurements were performed on individual CNCs under ambient conditions with 30% relative humidity (RH) and under a N 2 atmosphere with 0.1% RH. A procedure was also developed to calculate the CNC transverse elastic modulus (E T) by comparing the experimental force-distance curves measured on the CNCs with 3D finite element calculations of tip indentation on the CNC. The E T of an isolated CNC was estimated to be between 18 and 50 GPa at 0.1% RH; however, the associated crystallographic orientation of the CNC could not be determined. CNC properties were reasonably uniform along the entire CNC length, despite variations along the axis of 3-8 nm in CNC height. The range of RH used in this study was found to have a minimal effect on the CNC geometry, confirming the resistance of the cellulose crystals to water penetration. CNC flexibility was also investigated by using the AFM tip as a nanomanipulator.