Study of the formation of globule-like surface microstructures on polyacrylamide nano-films synthesized via electro-polymerization process (original) (raw)
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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...
Applied Surface Science, 2016
We used atomic force microscopy (AFM) to study surface morphology and kinetic roughening of Ag films. X-ray diffraction (XRD) technique is used to verify the films crystalline structure. The influence of film thickness on the kinetic roughening was investigated using AFM data and roughness calculation. It is revealed that the surface roughness increases with increasing the film thickness. The data also consist with a complex behavior which is called as anomalous scaling. Scaling laws analysis for Ag films presents two distinct dynamics including large local and scale roughness and indicates a power law dependency on the thickness of film. AFM images have been characterized by the multifractal analysis. This analysis shows that the selfsimilar and multifractal characteristics as well as anomalous scaling exist in the Ag film morphologies. Description of the quantitative growth and surface morphology was done by the multifractal spectra, f (˛) − ˛. It is found that the multifractal spectrum shape is left hook-like (that is difference of height interval of the multifractal spectrum, f = f (˛m in) −f (˛m ax) > 0). The results indicate that the surfaces having greater roughness give rise the wider multifractal spectrum width(˛) and the greater f, thus, the nonuniformity of the height probabilities becomes larger. It indicates that the multifractality of the films becomes more pronounced at the higher thickness.
Analysis of nano film by atomic force microscopy
2009
The corrosion inhibition efficiency of diethylenetriaminepenta(methylenephosphonic acid) (DTPMP) in combination with a bivalent cation like Zn2+ in controlling corrosion of mild steel immersed in rain water collected from rooftop, stored in concrete tank was investigated using weight loss method and electrochemical impedance spectroscopy. The combined corrosion inhibition efficiency offered by 50 ppm of DTPMP and 5 ppm of Zn2+ was 90%. The synergistic effect of the inhibiting compound was calculated. The corrosion inhibition was observed due to the formation of more stable and compact protective film on the metal surface. Fluorescence spectral analysis was used in detecting the presence of an iron - inhibitor complex and the coordination sites of the metal inhibitor with iron were determined by the FTIR spectra. The surface morphology of the protective film on the metal surface was characterized by using atomic force microscopy (AFM). .
Surface Mechanical Properties of Thin Polymer Films Investigated by AFM in Pulsed Force Mode
Langmuir, 2009
Atomic force microscopy in the pulsed force mode (PFM) is applied in this work to the study of thin dewetting patterns formed by drying an aqueous solution of poly(N-isopropylacrylamide) (PNIPAM) and sodium dodecyl sulfate (SDS) on mica. This technique allows the automated acquisition of typically 4 Â 10 6 force-distance curves on the sample surface together with maps showing nanodomains differentiated by their stiffness and adhesion to the tip. Topography images of dry films revealed a morphology formed by droplets distributed on the substrate. Adhesion and stiffness images with good lateral resolution show droplets containing polymer and surfactant contrasting with the substrate and also nanosized heterogeneities inside these droplets. They also revealed very small dewetted structures which could not be observed in the topography map by noncontact AFM. Adhesion interactions between the AFM tip and the polymer or the dewetted mica substrate were measured in terms of adhesion force and detachment energy, and can be used as new information to understand dewetting patterns containing silica particles, PNIPAM, and SDS. Other surface mechanical parameters such as stiffness, maximum indentation, hardness, compliance, hysteresis, and Young's modulus were obtained by sampling many points and used to characterize the PNIPAM/SDS films formed in the dewetting process.
Surface nanoscale imaging of collagen thin films by Atomic Force Microscopy
Materials Science and Engineering: C, 2013
Collagen, the most abundant protein in mammals, due to its unique properties is widely used as biomaterial, scaffold and culture substrate for cell and tissue regeneration studies. Since the majority of biological reactions occur on surfaces and structures at the nanoscale level it is of great importance to image the nanostructural surface of collagen based materials. The aim of this paper was to characterize, with Atomic Force Microscopy (AFM), collagen thin films formed on different substrates (glass, mica, polystyrene latex particle surfaces) and correlate their morphology with the used substrates, formation methodologies (spin coating, hydrodynamic flow) and original collagen solution. The results demonstrated that, by altering a number of parameters, it was possible to control the formation of collagen nanostructured films consisting of naturally occurring fibrils. The spin coating procedure enabled the formation of films with random oriented fibrils, while substrates influenced the fibril packing and surface roughness. The hydrodynamic flow was used for guiding fibril major orientation, while adsorption time, rinsing with buffer and solution concentration influenced the fibril orientation. The clarification of the contribution that different parameters had on thin film formation will enable the design and control of collagen nanobiomaterials with pre-determined characteristics.
Probing soft polymeric coatings of a capillary by atomic force microscopy
Journal of chromatography. B, Biomedical applications, 1996
Atomic force microscopy (AFM) has been used to probe the surface of a capillary after coating with "soft" polymers, notably polyacrylamides. The aim was the investigation of the efficiency of coverage of the silica surface, so as to reduce or eliminate the electroosmotic flow (EOF), particularly noxious in the separation of macromolecules. The quality of such coating is strongly dependent on two variables: temperature and pH. In the first case, progressively higher temperatures produce open silica patches, where no polymer seems to be bound. The transition from coated to largely uncoated surfaces occurs at 50 degrees C. Also the pH of the polymerizing solution strongly affects the coating efficiency. Since in all coating procedures the monomer solution is not buffered, addition of accelerator (TEMED, N,N,N'N'-tetramethylethylendiamine) induces polymer growth at pH 10-11. These pH values generate hydrolysis of the siloxane bridge anchoring the bifunctional agent (Bi...